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Firman RC, Ellis CM, Thorn S, Mawson PR. Parental effects on offspring sex ratio in the Numbat ( Myrmecobius fasciatus): does captivity influence paternal sex allocation? J Mammal 2023; 104:1036-1046. [PMID: 38033358 PMCID: PMC10682968 DOI: 10.1093/jmammal/gyad067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 06/03/2023] [Indexed: 12/02/2023] Open
Abstract
Sex allocation theories predict that under different ecological conditions the production of sons and daughters will affect parental fitness differently. Skewed offspring sex ratios often occur under captive conditions where individuals are exposed to nutritional and social conditions that differ from nature. Here, we analyzed 29 years of offspring sex ratio data from a captive population of an endangered marsupial, the Numbat (Myrmecobius fasciatus). We partitioned variation in offspring sex ratio based on parental origin (captive- vs. wild-bred), parental weight, maternal age, and maternal reproductive history. Our analyses revealed no effect of parental weight or maternal origin on offspring sex ratio-however, there was a significant effect of paternal origin. Data visualization indicated that captive-bred males tended to produce male-biased litters. We discuss the result in relation to recent studies that have shown that male mammals have the capacity to be arbiters of sex allocation and highlight candidate mechanisms, but consider it with caution due to the small sample size from which the result was derived. We performed a population viability analysis (PVA) to explore the potential impact of a sex ratio skew on the sustainability of the captive Numbat population under hypothetical scenarios. Our PVA revealed that supplementation with wild individuals is critical to the persistence of the captive Numbat population and that a biased sex ratio will lead to extinction of the captive colony under certain conditions. Overall, our study demonstrates that covert sex ratio skews can persist undetected in captive populations, which have the potential to become impactful and compromise population sustainability under changed management processes.
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Affiliation(s)
- Renée C Firman
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009, Australia
- School of Biological Sciences, University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009, Australia
| | - Connor M Ellis
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009, Australia
- School of Biological Sciences, University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009, Australia
| | - Sian Thorn
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009, Australia
| | - Peter R Mawson
- School of Biological Sciences, University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009, Australia
- Perth Zoo, Department of Biodiversity, Conservation and Attractions, 20 Labouchere Road, South Perth, Western Australia 6151, Australia
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2
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Smith KJ, Evans MJ, Gordon IJ, Pierson JC, Newport J, Manning AD. Analyzing captive breeding outcomes to inform reintroduction practice: lessons from the pookila ( Pseudomys novaehollandiae). J Mammal 2023; 104:1047-1061. [PMID: 37800101 PMCID: PMC10550247 DOI: 10.1093/jmammal/gyad056] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 05/04/2023] [Indexed: 10/07/2023] Open
Abstract
Captive breeding is often used to produce individuals for reintroduction programs in order to reestablish a species in an area where it has become locally extinct. To maximize the likelihood of establishing a self-sustaining population in the wild, an analysis of data from captive breeding programs is commonly undertaken to (1) increase the quantity of individuals and rate at which they can be released, and (2) maintain or improve the genetic and phenotypic quality of individuals. Here we demonstrate how the knowledge gained from these analyses can also be applied to decision-making during the design of subsequent reintroductions to further advance a reintroduction program toward success. We conducted an analysis of data from a captive breeding program for the threatened pookila (Pseudomys novaehollandiae, New Holland mouse) spanning 6 years. We found evidence for relationships between the reproductive output of pookila and behavioral, demographic, experiential, health, and physiological predictors. Based on a biological interpretation of these results, and with reference to a checklist of all known translocation tactics, we recommend 11 specific design elements to maximize the probability of pookila reproduction postrelease (thereby improving the likelihood of reintroduction success). These recommendations should be interpreted as hypotheses to be evaluated and refined in future reintroduction trials for the pookila. The uncertainty around the postrelease survival and reproduction of a species that is common in reintroduction practice warrants the creative use of existing data to inform adaptive management. Indeed, there is a wealth information in well-kept captive breeding records that is currently underused by reintroduction practitioners. The direct integration of knowledge derived from captive breeding (where available) with decision-making for reintroductions, as described here, will help navigate these uncertainties, which would benefit the conservation of both understudied and well-known species around the world.
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Affiliation(s)
- Kiarrah J Smith
- Fenner School of Environment and Society, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Maldwyn J Evans
- Fenner School of Environment and Society, The Australian National University, Acton, Australian Capital Territory 2601, Australia
- Department of Ecosystem Studies, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-0032, Japan
| | - Iain J Gordon
- Fenner School of Environment and Society, The Australian National University, Acton, Australian Capital Territory 2601, Australia
- The James Hutton Institute, Dundee DD2 5DA, United Kingdom
- Central Queensland University, Townsville, Queensland 4810, Australia
- Land and Water, CSIRO, Townsville, Queensland 4810, Australia
- Lead, Protected Places Mission, National Environmental Science Program, Reef and Rainforest Research Centre, Cairns, Queensland 4870, Australia
| | - Jennifer C Pierson
- Fenner School of Environment and Society, The Australian National University, Acton, Australian Capital Territory 2601, Australia
- Australian Wildlife Conservancy, Subiaco East, Western Australia 6008, Australia
- Centre for Conservation Ecology and Genomics, Institute for Applied Ecology, University of Canberra, Canberra, Australian Capital Territory 2617, Australia
| | - Jenny Newport
- Fenner School of Environment and Society, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Adrian D Manning
- Fenner School of Environment and Society, The Australian National University, Acton, Australian Capital Territory 2601, Australia
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3
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OUP accepted manuscript. J Mammal 2022. [DOI: 10.1093/jmammal/gyac041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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4
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Bodden C, Pang TY, Feng Y, Mridha F, Kong G, Li S, Watt MJ, Reichelt AC, Hannan AJ. Intergenerational effects of a paternal Western diet during adolescence on offspring gut microbiota, stress reactivity, and social behavior. FASEB J 2021; 36:e21981. [PMID: 34907601 DOI: 10.1096/fj.202100920rr] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 09/16/2021] [Accepted: 09/22/2021] [Indexed: 12/28/2022]
Abstract
The global consumption of highly processed, calorie-dense foods has contributed to an epidemic of overweight and obesity, along with negative consequences for metabolic dysfunction and disease susceptibility. As it becomes apparent that overweight and obesity have ripple effects through generations, understanding of the processes involved is required, in both maternal and paternal epigenetic inheritance. We focused on the patrilineal effects of a Western-style high-fat (21%) and high-sugar (34%) diet (WD) compared to control diet (CD) during adolescence and investigated F0 and F1 mice for physiological and behavioral changes. F0 males (fathers) showed increased body weight, impaired glycemic control, and decreased attractiveness to females. Paternal WD caused significant phenotypic changes in F1 offspring, including higher body weights of pups, increased Actinobacteria abundance in the gut microbiota (ascertained using 16S microbiome profiling), a food preference for WD pellets, increased male dominance and attractiveness to females, as well as decreased behavioral despair. These results collectively demonstrate the long-term intergenerational effects of a Western-style diet during paternal adolescence. The behavioral and physiological alterations in F1 offspring provide evidence of adaptive paternal programming via epigenetic inheritance. These findings have important implications for understanding paternally mediated intergenerational inheritance, and its relevance to offspring health and disease susceptibility.
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Affiliation(s)
- Carina Bodden
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Terence Y Pang
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Yingshi Feng
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Faria Mridha
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Geraldine Kong
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Shanshan Li
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Matthew J Watt
- Department of Anatomy and Physiology, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Amy C Reichelt
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia.,Department of Medical Sciences, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
| | - Anthony J Hannan
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Victoria, Australia.,Department of Anatomy and Physiology, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Victoria, Australia
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5
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Tidière M, Douay G, Müller P, Siberchicot A, Sliwa A, Whipple M, Douhard M. Lifespan decreases with proportion of sons in males but not females of zoo-housed tigers and lemurs. J Evol Biol 2021; 34:1061-1070. [PMID: 33914999 DOI: 10.1111/jeb.13793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 03/30/2021] [Accepted: 04/16/2021] [Indexed: 11/29/2022]
Abstract
Several studies have shown higher costs of rearing sons than daughters in mammals where males are larger than females. These studies typically focus on females by examining how the offspring sex ratio during a single reproductive event affected mothers' subsequent reproduction or survival probability. Here, we examine relationships between offspring sex ratio during single or multiple reproductive events and several survival metrics in mothers and fathers, using data from zoo-housed tigers (Panthera tigris) and ruffed lemurs (Varecia sp.). Our analyses failed to reveal an overall cost of reproduction or a higher cost of sons to mothers. In male ruffed lemurs, the proportion of sons produced during early life (before 10 years old) was negatively correlated with lifespan later in life. In tigers, males with a higher proportion of sons during their lifetime had shorter lifespans. One likely mechanism is the difference in testosterone levels between males: a high concentration of testosterone can increase the proportion of sons and compromise immune function. Our results suggest studies in wild populations should address the outstanding challenge of understanding consequences of sex allocation for males, and open an opportunity to predict lifespan in an applied conservation context.
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Affiliation(s)
- Morgane Tidière
- Université de Lyon, Laboratoire de Biométrie et Biologie Evolutive UMR5558 CNRS, Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Guillaume Douay
- Wildlife Reserves Singapore, Conservation, Research and Veterinary Department, Singapore
| | | | - Aurélie Siberchicot
- Université de Lyon, Laboratoire de Biométrie et Biologie Evolutive UMR5558 CNRS, Université Claude Bernard Lyon 1, Villeurbanne, France
| | | | | | - Mathieu Douhard
- Université de Lyon, Laboratoire de Biométrie et Biologie Evolutive UMR5558 CNRS, Université Claude Bernard Lyon 1, Villeurbanne, France
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6
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Toni P, Forsyth DM, Festa-Bianchet M. Determinants of offspring sex in kangaroos: a test of multiple hypotheses. Behav Ecol 2021. [DOI: 10.1093/beheco/araa131] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Abstract
When the fitness costs and benefits of sons and daughters differ, offspring sex ratio manipulation could be an important reproductive tactic. We explored the effects of environment and maternal caring ability on offspring sex to test four adaptive sex ratio modification hypotheses: the extrinsic modification hypothesis (EMH), carrying capacity hypothesis (CCH), Trivers-Willard hypothesis (TWH), and cost-of-reproduction hypothesis (CRH). The EMH and CCH propose that environmental conditions shape offspring sex ratios, directly or in interaction with maternal condition. The TWH and CRH predict a positive relationship between maternal condition and production of the costlier sex. The TWH predicts that mothers with superior caring ability should produce more of the sex that can provide the greatest fitness returns from additional maternal allocation, and the CRH proposes that females with limited caring ability should reduce fitness costs by producing the cheaper sex. Repeated measures on 83 known-age eastern gray kangaroos, polygynous marsupials with strong sexual dimorphism, revealed that offspring sex ratio was independent of per capita forage, supporting neither the EMH nor CCH, but was dependent on maternal mass, consistent with the TWH and CCH. Our results, however, cannot clearly identify the ultimate cause of the relationship between maternal mass and greater production of sons. One of the three assumptions of the TWH could not be verified, and mothers of sons suffered only marginal additional fitness costs. Sex ratios in higher vertebrates are likely not solely explained by factors dependent on maternal control.
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Affiliation(s)
- Pauline Toni
- Université de Sherbrooke, 2500 boulevard de l’Université, J1K2R1 Sherbrooke, Quebec, Canada
| | - David M Forsyth
- Vertebrate Pest Research Unit, New South Wales Department of Primary Industries, Orange, NSW, Australia
| | - Marco Festa-Bianchet
- Université de Sherbrooke, 2500 boulevard de l’Université, J1K2R1 Sherbrooke, Quebec, Canada
- Research School of Biology, The Australian National University, Canberra, ACT, Australia
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7
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Douhard M, Geffroy B. Males can adjust offspring sex ratio in an adaptive fashion through different mechanisms. Bioessays 2021; 43:e2000264. [PMID: 33594712 DOI: 10.1002/bies.202000264] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 01/26/2021] [Accepted: 01/26/2021] [Indexed: 01/15/2023]
Abstract
Sex allocation research has primarily focused on offspring sex-ratio adjustment by mothers. Yet, fathers also benefit from producing more of the sex with greater fitness returns. Here, we review the state-of-the art in the study of male-driven sex allocation and, counter to the current paradigm, we propose that males can adaptively influence offspring sex ratio through a wide variety of mechanisms. This includes differential production and motility of X- versus Y-bearing sperms in mammals, variation in seminal fluid composition in haplo-diploid invertebrates, and epigenetic mechanisms in some fish and lizards exhibiting environmental sex determination. Conflicts of interest between mothers and fathers over offspring sex ratios can emerge, although many more studies are needed in this area. While many studies of sex allocation have focused on adaptive explanations with little attention to mechanisms, and vice versa, the integration of these two topics is essential for understanding male-driven sex allocation.
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Affiliation(s)
- Mathieu Douhard
- Laboratoire de Biométrie & Biologie Evolutive, Université Lyon 1, Villeurbanne, France
| | - Benjamin Geffroy
- MARBEC, Univ Montpellier, Ifremer, CNRS, IRD, Palavas-Les-Flots, France
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8
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Firman RC, Tedeschi JN, Garcia-Gonzalez F. Sperm sex ratio adjustment in a mammal: perceived male competition leads to elevated proportions of female-producing sperm. Biol Lett 2020; 16:20190929. [PMID: 32486939 DOI: 10.1098/rsbl.2019.0929] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mammal sex allocation research has focused almost exclusively on maternal traits, but it is now apparent that fathers can also influence offspring sex ratios. Parents that produce female offspring under conditions of intense male-male competition can benefit with greater assurance of maximized grand-parentage. Adaptive adjustment in the sperm sex ratio, for example with an increase in the production of X-chromosome bearing sperm (CBS), is one potential paternal mechanism for achieving female-biased sex ratios. Here, we tested this mechanistic hypothesis by varying the risk of male-male competition that male house mice perceived during development, and quantifying sperm sex ratios at sexual maturity. Our analyses revealed that males exposed to a competitive 'risk' produced lower proportions of Y-CBS compared to males that matured under 'no risk' of competition. We also explored whether testosterone production was linked to sperm sex ratio variation, but found no evidence to support this. We discuss our findings in relation to the adaptive value of sperm sex ratio adjustments and the role of steroid hormones in socially induced sex allocation.
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Affiliation(s)
- Renée C Firman
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Jamie N Tedeschi
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Francisco Garcia-Gonzalez
- Centre for Evolutionary Biology, School of Biological Sciences (M092), The University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia.,Estacion Biológica de Doñana, CSIC, Sevilla, Spain
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9
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Firman RC. Exposure to high male density causes maternal stress and female-biased sex ratios in a mammal. Proc Biol Sci 2020; 287:20192909. [PMID: 32370673 PMCID: PMC7282911 DOI: 10.1098/rspb.2019.2909] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 04/14/2020] [Indexed: 12/29/2022] Open
Abstract
A shift from the traditional perspective that maternal stress is invariably costly has instigated recent interest into its adaptive role in offspring sex allocation. Stress generated by social instability has been linked to offspring sex ratio biases that favour the production of female offspring, which converges with the theoretical prediction that mothers in the poor condition are better off investing in daughters rather than sons. However, previous research has failed to disentangle two different processes: the passive consequence of maternal stress on sex-specific mortality and the adaptive effect of maternal stress at the time of conception. Here, I show that exposure to high male density social conditions leads to elevated stress hormone levels and female-biased in utero offspring sex ratios in house mice (Mus musculus domesticus), and identify that sex-specific offspring production-not sex-specific mortality-is the mechanism accounting for these sex ratio skews. This outcome reflects the optimal fitness scenario for mothers in a male-dominated environment: the production of daughters, who are guaranteed high mate availability, minimizes male-male competition for their sons. Overall, this study supports the idea that maternal stress has the potential to be adaptive and advances our understanding of how exposure to different social conditions can influence sex allocation in mammals.
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Affiliation(s)
- Renée C. Firman
- Centre for Evolutionary Biology, School of Biological Sciences, University of Western Australia, 35 Stirling Hwy, Crawley, Western Australia 6009, Australia
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10
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Martin MS, Owen M, Wintle NJP, Zhang G, Zhang H, Swaisgood RR. Stereotypic behaviour predicts reproductive performance and litter sex ratio in giant pandas. Sci Rep 2020; 10:7263. [PMID: 32350317 PMCID: PMC7190838 DOI: 10.1038/s41598-020-63763-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 04/01/2020] [Indexed: 11/09/2022] Open
Abstract
Breeding and welfare problems confront many conservation breeding programs. Stereotypies-repetitive, unvarying, functionless behaviours -are common abnormal behaviours that often arise in suboptimal conditions. While the role of stereotypies in welfare assessment is well studied, few investigations address the relationship between stereotypic behaviour and reproduction. We examined the correlation between stereotypic behaviour and reproductive performance in 101 giant pandas (Ailuropoda melanoleuca). High stereotyping males copulated more and produced more cubs, suggesting that highly sexually motivated males were prone to stereotypy but also had high reproductive competence. Female stereotypies were negatively associated with all reproductive measures closely tied to behavioural competence: high stereotyping females were less likely to copulate, less likely to mother-rear cubs, and-probably a result of poor maternal care-had lower cub survival. However, females that exhibited stereotypies were more likely to produce a cub, suggesting stereotypies are tied to behavioural but not physiological competence. High stereotyping female pandas also displayed strong and consistent bias toward production of female offspring while paternal relationship to sex allocation was the reverse. These results are consistent with stress-mediated sex allocation theory. Our findings raise concern about differential reproductive success among high and low stereotyping pandas, and possible genetic adaptation to captivity.
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Affiliation(s)
- Meghan S Martin
- Institute for Conservation Research, San Diego Zoo Global, 15600 San Pasqual Valley Rd., Escondido, California, 92027, USA.,PDXWildlife, 9233 SW Brier Pl., Portland, OR, 97219, USA
| | - Megan Owen
- Institute for Conservation Research, San Diego Zoo Global, 15600 San Pasqual Valley Rd., Escondido, California, 92027, USA
| | | | - Guiquan Zhang
- China Conservation and Research Center for the Giant Panda, Wolong, Sichuan, 623006, P.R. China
| | - Hemin Zhang
- China Conservation and Research Center for the Giant Panda, Wolong, Sichuan, 623006, P.R. China
| | - Ronald R Swaisgood
- Institute for Conservation Research, San Diego Zoo Global, 15600 San Pasqual Valley Rd., Escondido, California, 92027, USA.
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11
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Dias PAD, Montero Domínguez IL, Rangel Negrín A. Factors influencing infant sex ratio in howler monkeys (Alouatta spp.): A literature review and analysis. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 172:48-57. [PMID: 32141069 DOI: 10.1002/ajpa.24035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 02/11/2020] [Accepted: 02/19/2020] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Frequency-dependent selection is expected to maintain infant sex ratios around parity over evolutionary time. However, over ecological time periods, infant sex ratios vary, and it has been proposed that this variation may reflect adaptive processes. In primates, there are consistent patterns of variation in infant sex ratios, although their adaptive significance remains contentious. In addition to design issues, contrasting results could have derived across primates from variation in the fitness benefits accrued through sons or daughters associated with the specific social, ecological, and demographic context of populations. Thus, different sex allocation tactics could occur within species over time and space. METHODS We reviewed the literature to describe variation in infant sex ratio in howler monkeys (genus Alouatta) and to examine whether such a variation could be associated with adaptive sex allocation. We found 26 studies that provided data for this review. These studies yielded 96 infant sex reports, corresponding to 1,477 sexed infants. RESULTS Infant sex ratio across howler monkey species tends to parity, but females produce more sons under high group densities and more daughters when rainfall increases. DISCUSSION Based on these results, as well as on information on howler monkey dispersal patterns, demography, and within-group genetic relatedness, we speculate that, depending on population growth stage, sex allocation is explained by (a) local resource enhancement, that is, more cooperative philopatric daughters are produced when populations are growing; and (b) local resource competition, that is, more dispersing sons are produced when populations are saturated. Thus, there is evidence suggestive of adaptive variation in infant sex ratios in howler monkeys.
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Affiliation(s)
- Pedro A D Dias
- Primate Behavioral Ecology Lab, Instituto de Neuroetología, Universidad Veracruzana, Xalapa, Veracruz, Mexico
| | - Irma L Montero Domínguez
- Primate Behavioral Ecology Lab, Instituto de Neuroetología, Universidad Veracruzana, Xalapa, Veracruz, Mexico
| | - Ariadna Rangel Negrín
- Primate Behavioral Ecology Lab, Instituto de Neuroetología, Universidad Veracruzana, Xalapa, Veracruz, Mexico
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12
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Scherb H, Kusmierz R, Voigt K. Secondary sex ratio and trends in the associated gender-specific births near nuclear facilities in France and Germany: Update of birth counts. Reprod Toxicol 2019; 89:159-167. [DOI: 10.1016/j.reprotox.2019.07.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 07/19/2019] [Accepted: 07/24/2019] [Indexed: 12/12/2022]
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13
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Martins ACL, Vaz MA, Macedo MM, Santos RL, Galdino CAB, Wenceslau RR, Valle GR. Maternal age, paternal age, and litter size interact to affect the offspring sex ratio of German Shepherd dogs. Theriogenology 2019; 135:169-173. [DOI: 10.1016/j.theriogenology.2019.06.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 03/25/2019] [Accepted: 06/11/2019] [Indexed: 11/25/2022]
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14
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The global male-bias in sex ratio at birth is sustained by the sex ratio genotypes of replacement offspring. Genetica 2019; 147:249-258. [DOI: 10.1007/s10709-019-00074-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 07/18/2019] [Indexed: 10/26/2022]
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15
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Lavoie MD, Tedeschi JN, Garcia-Gonzalez F, Firman RC. Exposure to male-dominated environments during development influences sperm sex ratios at sexual maturity. Evol Lett 2019; 3:392-402. [PMID: 31388448 PMCID: PMC6675145 DOI: 10.1002/evl3.123] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 04/15/2019] [Accepted: 05/21/2019] [Indexed: 11/18/2022] Open
Abstract
Different stages during development are important when it comes to phenotypic adjustments in response to external stimuli. Critical stages in mammals are the prenatal phase, where embryos are exposed to a milieu of sex steroid hormones, and the early‐postnatal phase, where littermates interact and experience their incipient social environment. Further, the postmaternal environment will influence the development of traits that are linked to reproductive success in adulthood. Accumulated evidence of male‐driven sex allocation establishes the currently untested hypothesis that the sperm sex ratio is a plastic trait that can be mediated to align with prevailing social conditions. Here, we used natural variation in the maternal environment and experimentally manipulated the postmaternal environment to identify the importance of these developmental phases on sperm sex ratio adjustments in wild house mice (Mus musculus domesticus). We found that male density in both environments was predictive of sperm sex ratios at sexual maturity: males from more male‐biased litters and males maturing under high male density produced elevated levels of Y‐chromosome‐bearing sperm. Our findings indicate that the sperm sex ratio is a variable phenotypic trait that responds to the external environment, and highlight the potential that these adjustments function as a mechanism of male‐driven sex allocation.
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Affiliation(s)
- Misha D Lavoie
- School of Biological Sciences (M092), Centre for Evolutionary Biology The University of Western Australia Crawley WA 6009 Australia
| | - Jamie N Tedeschi
- School of Biological Sciences (M092), Centre for Evolutionary Biology The University of Western Australia Crawley WA 6009 Australia
| | - Francisco Garcia-Gonzalez
- School of Biological Sciences (M092), Centre for Evolutionary Biology The University of Western Australia Crawley WA 6009 Australia.,Estacion Biológica de Doñana CSIC Sevilla Spain
| | - Renée C Firman
- School of Biological Sciences (M092), Centre for Evolutionary Biology The University of Western Australia Crawley WA 6009 Australia
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16
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Festa‐Bianchet M, Côté SD, Hamel S, Pelletier F. Long‐term studies of bighorn sheep and mountain goats reveal fitness costs of reproduction. J Anim Ecol 2019; 88:1118-1133. [DOI: 10.1111/1365-2656.13002] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 03/20/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Marco Festa‐Bianchet
- Département de biologie Université de Sherbrooke Sherbrooke Québec Canada
- Centre d'études nordiques Québec City Québec Canada
| | - Steeve D. Côté
- Centre d'études nordiques Québec City Québec Canada
- Département de biologie Université Laval Sainte‐Foy Québec Canada
| | - Sandra Hamel
- Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries, and Economics UiT The Arctic University of Norway Tromsø Norway
| | - Fanie Pelletier
- Département de biologie Université de Sherbrooke Sherbrooke Québec Canada
- Centre d'études nordiques Québec City Québec Canada
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17
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Vanthournout B, Busck MM, Bechsgaard J, Hendrickx F, Schramm A, Bilde T. Male spiders control offspring sex ratio through greater production of female-determining sperm. Proc Biol Sci 2019; 285:rspb.2017.2887. [PMID: 29563266 DOI: 10.1098/rspb.2017.2887] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 02/26/2018] [Indexed: 01/07/2023] Open
Abstract
Sex allocation theory predicts that when sons and daughters have different reproductive values, parents should adjust offspring sex ratio towards the sex with the higher fitness return. Haplo-diploid species directly control offspring sex ratio, but species with chromosomal sex determination (CSD) were presumed to be constrained by Mendelian segregation. There is now increasing evidence that CSD species can adjust sex ratio strategically, but the underlying mechanism is not well understood. One hypothesis states that adaptive control is more likely to evolve in the heterogametic sex through a bias in gamete production. We investigated this hypothesis in males as the heterogametic sex in two social spider species that consistently show adaptive female-biased sex ratio and in one subsocial species that is characterized by equal sex ratio. We quantified the production of male (0) and female (X) determining sperm cells using flow cytometry, and show that males of social species produce significantly more X-carrying sperm than 0-sperm, on average 70%. This is consistent with the production of more daughters. Males of the subsocial species produced a significantly lower bias of 54% X-carrying sperm. We also investigated whether inter-genomic conflict between hosts and their endosymbionts may explain female bias. Next generation sequencing showed that five common genera of bacterial endosymbionts known to affect sex ratio are largely absent, ruling out that endosymbiont bacteria bias sex ratio in social spiders. Our study provides evidence for paternal control over sex allocation through biased gamete production as a mechanism by which the heterogametic sex in CSD species adaptively adjust offspring sex ratio.
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Affiliation(s)
- Bram Vanthournout
- Department of Bioscience, Section for Genetics, Ecology and Evolution, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus C, Denmark.,Biology Department, Evolution and Optics of Nanostructures Group, Ghent University, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
| | - Mette Marie Busck
- Department of Bioscience, Section for Microbiology, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus C, Denmark
| | - Jesper Bechsgaard
- Department of Bioscience, Section for Genetics, Ecology and Evolution, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus C, Denmark
| | - Frederik Hendrickx
- Biology Department, Terrestrial Ecology Unit, Ghent University, K.L. Ledeganckstraat 35, 9000 Gent, Belgium.,Entomology Department, Royal Belgian Institute of Natural Sciences, Vautierstraat 29, 1000 Brussels, Belgium
| | - Andreas Schramm
- Department of Bioscience, Section for Microbiology, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus C, Denmark
| | - Trine Bilde
- Department of Bioscience, Section for Genetics, Ecology and Evolution, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus C, Denmark
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18
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Ceacero F, Komárková M, García AJ, Gallego L. Different maternal investment strategies for male and female calves in a polygynous mammal. Curr Zool 2019; 65:269-277. [PMID: 31263485 PMCID: PMC6595534 DOI: 10.1093/cz/zoy049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Accepted: 06/25/2018] [Indexed: 11/14/2022] Open
Abstract
Maternal effects occur when the phenotype of the mother influences that of the young to the detriment of her survival, growth or fitness. The investment of the mother can be affected by maternal body condition and/or experience. Trivers-Willard Hypothesis (TWH) and Local Resource Competition Hypothesis (LRCH) are the main hypotheses used to explain bias in birth sex-ratios in mammals, as well as for sex-biased maternal investment. Both hypotheses suggest that a different amount of investment must be expected according to the sex of the young. However, recent studies suggest that these differences are not in quantity but in the strategies: mechanisms and objectives may differ for each sex. We studied how maternal characteristics (age, body mass, body condition, and dominance status) influence relevant aspects of the birth and early growth of the calf (birth date, birth body mass, body mass at weaning, and body condition at weaning) separately for each sex; and how that investment is mediated by milk production and composition (lactose, fat, and protein). One hundred eighty-eight newborns from 75 captive red deer hinds aged from 2 to 19 years were analyzed. The main differential investment observed was related to birth date: when producing a female, hinds give birth earlier in the season only if they have a good body condition; however, when gestating a male it is the older hinds those which deliver earlier. Subsequently, milk production and composition are correlated with birth body mass in female calves, but to weaning body mass in males. Thus, only hind body mass affects the weaning body mass of female calves, compared with age and hind body mass in males. These results suggest that while TWH fits the maternal investment strategy found for male calves, it is LRCH which correlates with the maternal investment patterns observed for females.
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Affiliation(s)
- Francisco Ceacero
- Department of Animal Science and Food Processing, Faculty of Tropical AgriSciences, Czech University of Life Sciences, Kamýcká 129, 165 00 Praha 6 - Suchdol, Czech Republic
| | - Martina Komárková
- Department of Ethology, Institute of Animal Science, Přátelství 815, 104 01 Praha - Uhříněves, Czech Republic
| | - Andrés J García
- Instituto de Investigación en Recursos Cinegéticos (IREC), Consejo Superior de Investigaciones Científicas—Universidad de Castilla-La Mancha—Junta de Comunidades de Castilla-La Mancha (CSIC-UCLM-JCCM), Ronda de Toledo s/n, Ciudad Real, Spain
- Sección de Recursos Cinegéticos y Ganaderos, Instituto de Desarrollo Regional (IDR), Albacete, Spain
- Departamento de Ciencia y Tecnología Agroforestal y Genética, ETSIAM, Universidad de Castilla-La Mancha (UCLM), Albacete, Spain
| | - Laureano Gallego
- Departamento de Ciencia y Tecnología Agroforestal y Genética, ETSIAM, Universidad de Castilla-La Mancha (UCLM), Albacete, Spain
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19
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Malo AF, Gilbert TC, Riordan P. Drivers of sex ratio bias in the eastern bongo: lower inbreeding increases the probability of being born male. Proc Biol Sci 2019; 286:20190345. [PMID: 31064305 PMCID: PMC6532524 DOI: 10.1098/rspb.2019.0345] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 04/14/2019] [Indexed: 01/13/2023] Open
Abstract
Parent sex ratio allocation has consequences for individual fitness, population dynamics, and conservation. Theory predicts that parents should adjust offspring sex ratio when the fitness returns of producing male or female offspring varies. Previous studies have assumed that only mothers are capable of biasing offspring sex ratios, but have neglected fathers, given the expectation of an equal proportion of X- and Y-chromosome-bearing (CBS) sperm in ejaculates due to sex chromosome segregation at meiosis. This assumption has been recently refuted and both paternal fertility and paternal genetic quality have been shown to bias sex ratios. Here, we simultaneously test the relative contribution of paternal, maternal, and individual genetic quality, as measured by inbreeding, on the probability of being born a son or a daughter, using pedigree and lifelong offspring sex ratio data for the eastern bongo ( Tragelaphus eurycerus isaaci). Our models showed first, that surprisingly, as individual inbreeding decreases the probability of being born male increases, second, that paternal genetic effects on sex ratio were stronger than maternal genetic effects (which were absent). Furthermore, paternal effects were opposite in sign to those predicted; father inbreeding increases the probability of having sons. Previous paternal effects have been interpreted as adaptive due to sex-specific inbreeding depression for reproductive traits. We argue that in the eastern bongo, the opposite sign of the paternal effect on sex ratios results from a reversed sex-specific inbreeding depression pattern (present for female but not male reproductive traits). We anticipate that this research will help stimulate research on evolutionary constraints to sex ratios. Finally, the results open a new avenue of research to predict sex ratio allocation in an applied conservation context. Future models of sex ratio allocation should also include the predicted inbreeding level of the offspring and paternal inbreeding levels.
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Affiliation(s)
- Aurelio F. Malo
- GLOCEE - Global Change Ecology and Evolution Group, Department of Life Sciences, Universidad de Alcalá, 28871, Spain
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK
| | - Tania C. Gilbert
- Marwell Wildlife, Thompsons Lane, Winchester, Hampshire SO21 1JH, UK
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Philip Riordan
- Marwell Wildlife, Thompsons Lane, Winchester, Hampshire SO21 1JH, UK
- School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Southampton SO17 1BJ, UK
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20
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The Adaptive Sex in Stressful Environments. Trends Ecol Evol 2019; 34:628-640. [PMID: 30952545 DOI: 10.1016/j.tree.2019.02.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 02/18/2019] [Accepted: 02/19/2019] [Indexed: 01/10/2023]
Abstract
The impact of early stress on juvenile development has intrigued scientists for decades, but the adaptive significance of such effects remains an ongoing debate. This debate has largely ignored some characteristics of the offspring, such as their sex, despite strong evolutionary and demographic implications of sex-ratio variation. We review recent studies that examine associations between glucocorticoids (GCs), the main class of stress hormones, and offspring sex. Whereas exposure to GCs at around the time of sex determination in fish consistently produces males, the extent and direction of sex-ratio bias in response to stress vary in reptiles, birds, and mammals. We propose proximate and ultimate explanations for most of these trends.
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21
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Edwards AM, Cameron EZ, Deakin JE, Ezaz T, Pereira JC, Ferguson‐Smith MA, Robert KA. Sexual conflict in action: An antagonistic relationship between maternal and paternal sex allocation in the tammar wallaby, Notamacropus eugenii. Ecol Evol 2019; 9:4340-4348. [PMID: 31031909 PMCID: PMC6476839 DOI: 10.1002/ece3.4813] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Accepted: 11/22/2018] [Indexed: 01/29/2023] Open
Abstract
Sex ratio biases are often inconsistent, both among and within species and populations. While some of these inconsistencies may be due to experimental design, much of the variation remains inexplicable. Recent research suggests that an exclusive focus on mothers may account for some of the inconsistency, with an increasing number of studies showing variation in sperm sex ratios and seminal fluids. Using fluorescent in-situ hybridization, we show a significant population-level Y-chromosome bias in the spermatozoa of wild tammar wallabies, but with significant intraindividual variation between males. We also show a population-level birth sex ratio trend in the same direction toward male offspring, but a weaning sex ratio that is significantly female-biased, indicating that males are disproportionately lost during lactation. We hypothesize that sexual conflict between parents may cause mothers to adjust offspring sex ratios after birth, through abandonment of male pouch young and reactivation of diapaused embryos. Further research is required in a captive, controlled setting to understand what is driving and mechanistically controlling sperm sex ratio and offspring sex ratio biases and to understand the sexually antagonistic relationship between mothers and fathers over offspring sex. These results extend beyond sex allocation, as they question studies of population processes that assume equal input of sex chromosomes from fathers, and will also assist with future reproduction studies for management and conservation of marsupials.
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Affiliation(s)
- Amy M. Edwards
- Department of Ecology, Environment and Evolution, School of Life SciencesLa Trobe UniversityMelbourneVictoriaAustralia
| | - Elissa Z. Cameron
- School of Biological SciencesUniversity of CanterburyChristchurchNew Zealand
| | - Janine E. Deakin
- Institute for Applied EcologyUniversity of CanberraCanberraAustralian Capital TerritoryAustralia
| | - Tariq Ezaz
- Institute for Applied EcologyUniversity of CanberraCanberraAustralian Capital TerritoryAustralia
| | - Jorge C. Pereira
- Department of Veterinary MedicineUniversity of CambridgeCambridgeUK
- Cytocell Ltd.CambridgeUK
| | | | - Kylie A. Robert
- Department of Ecology, Environment and Evolution, School of Life SciencesLa Trobe UniversityMelbourneVictoriaAustralia
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22
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Edwards AM, Cameron EZ, Wapstra E, McEvoy J. Maternal effects obscure condition-dependent sex allocation in changing environments. ROYAL SOCIETY OPEN SCIENCE 2019; 6:181885. [PMID: 31183124 PMCID: PMC6502394 DOI: 10.1098/rsos.181885] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 03/05/2019] [Indexed: 06/09/2023]
Abstract
Climate change increases environmental fluctuations which thereby impact population demography. Species with temperature-dependent sex determination may experience more extreme sex ratio skews, but this has not been considered in species with chromosomally determined sex. However, anticipatory maternal effects cause lifelong physiological changes impacting sex ratios. Here we show, in mice, that more sons were born to mothers in good condition when their breeding environment matched their gestational environment, consistent with theoretical predictions, but mothers in mismatched environments have no condition-sex ratio relationship. Thus, the predicted effect of condition on sex ratio was obscured by maternal effects when the environment changed. This may explain extreme sex ratio skews in reintroduced or translocated populations, and sex ratio skews may become more common and less predictable with accelerating environmental change.
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Affiliation(s)
- A. M. Edwards
- Department of Ecology, Environment and Evolution, La Trobe University, Bundoora, Victoria 3086, Australia
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia
| | - E. Z. Cameron
- School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, Tasmania 7001, Australia
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
| | - E. Wapstra
- Department of Ecology, Environment and Evolution, La Trobe University, Bundoora, Victoria 3086, Australia
| | - J. McEvoy
- Department of Ecology, Environment and Evolution, La Trobe University, Bundoora, Victoria 3086, Australia
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23
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Ross KG, Shoemaker D. Unexpected patterns of segregation distortion at a selfish supergene in the fire ant Solenopsis invicta. BMC Genet 2018; 19:101. [PMID: 30404617 PMCID: PMC6223060 DOI: 10.1186/s12863-018-0685-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 10/12/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The Sb supergene in the fire ant Solenopsis invicta determines the form of colony social organization, with colonies whose inhabitants bear the element containing multiple reproductive queens and colonies lacking it containing only a single queen. Several features of this supergene - including suppressed recombination, presence of deleterious mutations, association with a large centromere, and "green-beard" behavior - suggest that it may be a selfish genetic element that engages in transmission ratio distortion (TRD), defined as significant departures in progeny allele frequencies from Mendelian inheritance ratios. We tested this possibility by surveying segregation ratios in embryo progenies of 101 queens of the "polygyne" social form (3512 embryos) using three supergene-linked markers and twelve markers outside the supergene. RESULTS Significant departures from Mendelian ratios were observed at the supergene loci in 3-5 times more progenies than expected in the absence of TRD and than found, on average, among non-supergene loci. Also, supergene loci displayed the greatest mean deviations from Mendelian ratios among all study loci, although these typically were modest. A surprising feature of the observed inter-progeny variation in TRD was that significant deviations involved not only excesses of supergene alleles but also similarly frequent excesses of the alternate alleles on the homologous chromosome. As expected given the common occurrence of such "drive reversal" in this system, alleles associated with the supergene gain no consistent transmission advantage over their alternate alleles at the population level. Finally, we observed low levels of recombination and incomplete gametic disequilibrium across the supergene, including between adjacent markers within a single inversion. CONCLUSIONS Our data confirm the prediction that the Sb supergene is a selfish genetic element capable of biasing its own transmission during reproduction, yet counterselection for suppressor loci evidently has produced an evolutionary stalemate in TRD between the variant homologous haplotypes on the "social chromosome". Evidence implicates prezygotic segregation distortion as responsible for the TRD we document, with "true" meiotic drive the most likely mechanism. Low levels of recombination and incomplete gametic disequilibrium across the supergene suggest that selection does not preserve a single uniform supergene haplotype responsible for inducing polygyny.
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Affiliation(s)
- Kenneth G. Ross
- Department of Entomology, University of Georgia, Athens, GA USA
| | - DeWayne Shoemaker
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN USA
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24
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Malo AF, Martinez-Pastor F, Garcia-Gonzalez F, Garde J, Ballou JD, Lacy RC. A father effect explains sex-ratio bias. Proc Biol Sci 2018; 284:rspb.2017.1159. [PMID: 28855362 DOI: 10.1098/rspb.2017.1159] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 07/19/2017] [Indexed: 11/12/2022] Open
Abstract
Sex ratio allocation has important fitness consequences, and theory predicts that parents should adjust offspring sex ratio in cases where the fitness returns of producing male and female offspring vary. The ability of fathers to bias offspring sex ratios has traditionally been dismissed given the expectation of an equal proportion of X- and Y-chromosome-bearing sperm (CBS) in ejaculates due to segregation of sex chromosomes at meiosis. This expectation has been recently refuted. Here we used Peromyscus leucopus to demonstrate that sex ratio is explained by an exclusive effect of the father, and suggest a likely mechanism by which male-driven sex-ratio bias is attained. We identified a male sperm morphological marker that is associated with the mechanism leading to sex ratio bias; differences among males in the sperm nucleus area (a proxy for the sex chromosome that the sperm contains) explain 22% variation in litter sex ratio. We further show the role played by the sperm nucleus area as a mediator in the relationship between individual genetic variation and sex-ratio bias. Fathers with high levels of genetic variation had ejaculates with a higher proportion of sperm with small nuclei area. This, in turn, led to siring a higher proportion of sons (25% increase in sons per 0.1 decrease in the inbreeding coefficient). Our results reveal a plausible mechanism underlying unexplored male-driven sex-ratio biases. We also discuss why this pattern of paternal bias can be adaptive. This research puts to rest the idea that father contribution to sex ratio variation should be disregarded in vertebrates, and will stimulate research on evolutionary constraints to sex ratios-for example, whether fathers and mothers have divergent, coinciding, or neutral sex allocation interests. Finally, these results offer a potential explanation for those intriguing cases in which there are sex ratio biases, such as in humans.
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Affiliation(s)
- Aurelio F Malo
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK .,Chicago Zoological Society, Brookfield, IL, USA.,Smithsonian Conservation Biology Institute, Washington, DC, USA
| | - Felipe Martinez-Pastor
- SaBio IREC (CSIC-UCLM-JCCM), Campus Universitario s. n. 02071, Albacete, Spain.,INDEGSAL and Molecular Biology (Cell Biology), University of León, León, Spain
| | - Francisco Garcia-Gonzalez
- Estacion Biológica de Doñana, CSIC, Sevilla, Spain.,Centre for Evolutionary Biology, The University of Western Australia, Crawley, Western Australia, Australia
| | - Julián Garde
- SaBio IREC (CSIC-UCLM-JCCM), Campus Universitario s. n. 02071, Albacete, Spain
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25
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Affiliation(s)
- Mathieu Douhard
- Département de Biologie; Université de Sherbrooke; 2500 boulevard de l’ Université Sherbrooke QC J1K 2R1 Canada
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26
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27
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Douhard M. Offspring sex ratio in mammals and the Trivers-Willard hypothesis: In pursuit of unambiguous evidence. Bioessays 2017; 39. [DOI: 10.1002/bies.201700043] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Mathieu Douhard
- Département de Biologie; Université de Sherbrooke; Sherbrooke Québec Canada
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28
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Abstract
The human sex ratio (proportion male) at birth (SRB) varies with many variables. Some of this variation has an established proximate cause. For instance, low SRB (more females) at birth are associated with various forms of stressful events or circumstances during or prior to pregnancy. These low SRB are almost certainly mainly caused by maternal-stress-induced male foetal loss. Other types of SRB variation are thought to be caused by hormonal variation in either or both parents around the time of conception. One or other of these two types of proximate cause seems to be responsible for most of the established variation of SRB. This will be illustrated here in respect of some selected forms of SRB variation. It seems likely that a clarification of the hormonal causes of SRB variation will also help explain the striking (apparent) inconsistencies in the results of reported tests of the influential Trivers-Willard hypothesis. It is further proposed that an appreciation of the evidence that parental hormones influence SRB may enhance understanding of several important pathologies (hepatitis B, toxoplasmosis, testicular cancer, prostate cancer and autism).
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Affiliation(s)
- William H James
- The Galton Laboratory, Department of Genetics, Evolution and Environment, University College London, United Kingdom.
| | - Victor Grech
- Department of Paediatrics, Mater Dei Hospital Medical School, Malta.
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29
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Delpietro HA, Russo RG, Carter GG, Lord RD, Delpietro GL. Reproductive seasonality, sex ratio and philopatry in Argentina's common vampire bats. ROYAL SOCIETY OPEN SCIENCE 2017; 4:160959. [PMID: 28484615 PMCID: PMC5414252 DOI: 10.1098/rsos.160959] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 03/20/2017] [Indexed: 05/09/2023]
Abstract
Common vampire bats (Desmodus rotundus) are a key rabies vector in South America. Improved management of this species requires long-term, region-specific information. To investigate patterns of demography and dispersal, we analysed 13 642 captures of common vampire bats in Northern Argentina from the period 1969-2004. In contrast with findings from more tropical regions, we found reproductive seasonality with peak pregnancy in September and peak lactation in February. Curiously, sex ratios were consistently male-biased both in maternity roosts and at foraging sites. Males comprised 57% of 9509 adults caught at night, 57% of 1078 juveniles caught at night, 57% of 603 juveniles caught in roosts during the day, and 55% of 103 newborns and mature fetuses. Most observed roosts were in man-made structures. Movements of 1.5-54 km were most frequent in adult males, followed by young males, adult females and young females. At night, males visited maternity roosts, and non-pregnant, non-lactating females visited bachelor roosts. Males fed earlier in the night. Finally, we report new longevity records for free-ranging vampire bats: 16 and 17 years of age for a female and male, respectively. Our results are consistent with model predictions that sex-biased movements might play a key role in rabies transmission between vampire bat populations.
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Affiliation(s)
- H. A. Delpietro
- Servicio Nacional de Sanidad y Calidad Agroalimentaria (SENASA), Posadas, Argentina
- e-mail:
| | - R. G. Russo
- Servicio Nacional de Sanidad y Calidad Agroalimentaria (SENASA), Posadas, Argentina
| | - G. G. Carter
- Smithsonian Tropical Research Institute, Panama, Republic of Panama
| | - R. D. Lord
- Formerly of the Pan American Health Organization, Reading, PA, USA
| | - G. L. Delpietro
- Servicio Nacional de Sanidad y Calidad Agroalimentaria (SENASA), Posadas, Argentina
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30
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Edwards AM, Cameron EZ. Cryptic male choice: experimental evidence of sperm sex ratio and seminal fluid adjustment in relation to coital rate. Reprod Fertil Dev 2017; 29:1401-1404. [DOI: 10.1071/rd16123] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/16/2016] [Indexed: 11/23/2022] Open
Abstract
The differential allocation hypothesis suggests that a mother should adjust the sex of offspring in relation to her mate’s attractiveness, thereby increasing future reproductive fitness when her sons inherit the attractive traits. More attractive males have been shown to sire more sons, but it is possible that the sex ratio skew could be a result of paternal rather than maternal manipulation, which would be a more parsimonious explanation. We manipulated coital rate (an indicator of attractiveness) in laboratory mice and showed that males that mate more often have higher levels of glucose in their semen despite lower blood glucose levels. Since peri-conceptual glucose levels in utero increase male conceptus survival, this could result in male-biased sex ratios. The males that mated most also had more remaining X-chromosome-bearing-spermatozoa, suggesting depletion of Y-chromosome-bearing-spermatozoa during mating. We hypothesise that males may alter both seminal fluids and X : Y ratios in an ejaculate to influence subsequent sex ratios. Our results further support a paternal role in sex allocation.
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31
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Cameron EZ, Edwards AM, Parsley LM. Developmental sexual dimorphism and the evolution of mechanisms for adjustment of sex ratios in mammals. Ann N Y Acad Sci 2016; 1389:147-163. [PMID: 27862006 DOI: 10.1111/nyas.13288] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Revised: 09/28/2016] [Accepted: 10/05/2016] [Indexed: 12/15/2022]
Abstract
Sex allocation theory predicts biased offspring sex ratios in relation to local conditions if they would maximize parental lifetime reproductive return. In mammals, the extent of the birth sex bias is often unpredictable and inconsistent, leading some to question its evolutionary significance. For facultative adjustment of sex ratios to occur, males and females would need to be detectably different from an early developmental stage, but classic sexual dimorphism arises from hormonal influences after gonadal development. Recent advances in our understanding of early, pregonadal sexual dimorphism, however, indicate high levels of dimorphism in gene expression, caused by chromosomal rather than hormonal differences. Here, we discuss how such dimorphism would interact with and link previously hypothesized mechanisms for sex-ratio adjustment. These differences between males and females are sufficient for offspring sex both to be detectable to parents and to provide selectable cues for biasing sex ratios from the earliest stages. We suggest ways in which future research could use the advances in our understanding of sexually dimorphic developmental physiology to test the evolutionary significance of sex allocation in mammals. Such an approach would advance our understanding of sex allocation and could be applied to other taxa.
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Affiliation(s)
- Elissa Z Cameron
- School of Biological Sciences, University of Tasmania, Hobart, Australia.,School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Amy M Edwards
- School of Biological Sciences, University of Tasmania, Hobart, Australia
| | - Laura M Parsley
- School of Biological Sciences, University of Tasmania, Hobart, Australia
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32
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Edwards AM, Cameron EZ, Pereira JC, Wapstra E, Ferguson-Smith MA, Horton SR, Thomasson K. Gestational experience alters sex allocation in the subsequent generation. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160210. [PMID: 27493776 PMCID: PMC4968468 DOI: 10.1098/rsos.160210] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/08/2016] [Indexed: 06/06/2023]
Abstract
Empirical tests of adaptive maternal sex allocation hypotheses have presented inconsistent results in mammals. The possibility that mothers are constrained in their ability to adjust sex ratios could explain some of the remaining variation. Maternal effects, the influence of the maternal phenotype or genotype on her developing offspring, may constrain sex allocation through physiological changes in response to the gestational environment. We tested if maternal effects constrain future parental sex allocation through a lowered gestational stress environment in laboratory mice. Females that experienced lowered stress as embryos in utero gave birth to female-biased litters as adults, with no change to litter size. Changes in offspring sex ratio was linked to peri-conceptual glucose, as those females that had increasing blood glucose peri-conceptionally gave birth to litters with a higher male to female sex ratio. There was, however, no effect of the lowered prenatal stress for developing male embryos and their sperm sex ratio when adult. We discuss the implications of maternal effects and maternal stress environment on the lifelong physiology of the offspring, particularly as a constraint on later maternal sex allocation.
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Affiliation(s)
- A. M. Edwards
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - E. Z. Cameron
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - J. C. Pereira
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
- Cytocell Ltd., Cambridge Technopark, Newmarket Road, Cambridge, UK
| | - E. Wapstra
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | | | - S. R. Horton
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | - K. Thomasson
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
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Paternal under-nutrition programs metabolic syndrome in offspring which can be reversed by antioxidant/vitamin food fortification in fathers. Sci Rep 2016; 6:27010. [PMID: 27255552 PMCID: PMC4891691 DOI: 10.1038/srep27010] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 05/11/2016] [Indexed: 12/31/2022] Open
Abstract
There is an ever increasing body of evidence that demonstrates that paternal over-nutrition prior to conception programs impaired metabolic health in offspring. Here we examined whether paternal under-nutrition can also program impaired health in offspring and if any detrimental health outcomes in offspring could be prevented by micronutrient supplementation (vitamins and antioxidants). We discovered that restricting the food intake of male rodents reduced their body weight, fertility, increased sperm oxidative DNA lesions and reduced global sperm methylation. Under-nourished males then sired offspring with reduced postnatal weight and growth but somewhat paradoxically increased adiposity and dyslipidaemia, despite being fed standard chow. Paternal vitamin/antioxidant food fortification during under-nutrition not only normalised founder oxidative sperm DNA lesions but also prevented early growth restriction, fat accumulation and dyslipidaemia in offspring. This demonstrates that paternal under-nutrition reduces postnatal growth but increases the risk of obesity and metabolic disease in the next generation and that micronutrient supplementation during this period of under-nutrition is capable of restoring offspring metabolic health.
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Are there physiological constraints on maternal ability to adjust sex ratios in mammals? J Zool (1987) 2016. [DOI: 10.1111/jzo.12327] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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Scherb H, Kusmierz R, Voigt K. Human sex ratio at birth and residential proximity to nuclear facilities in France. Reprod Toxicol 2016; 60:104-11. [PMID: 26880420 DOI: 10.1016/j.reprotox.2016.02.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 01/15/2016] [Accepted: 02/05/2016] [Indexed: 10/22/2022]
Abstract
The possible detrimental genetic impact on humans living in the vicinity of nuclear facilities has been previously studied. We found evidence for an increase in the human secondary sex ratio (sex odds) within distances of up to 35km from nuclear facilities in Germany and Switzerland. Here, we extend our pilot investigations using new comprehensive data from France. The French data (1968-2011) account for 36,565 municipalities with 16,968,701 male and 16,145,925 female births. The overall sex ratio was 1.0510. Using linear and nonlinear logistic regression models with dummy variables coding for appropriately grouped municipalities, operation time periods, and corresponding spatiotemporal interactions, we consider the association between annual municipality-level birth sex ratios and minimum distances of municipalities from nuclear facilities. Within 35km from 28 nuclear sites in France, the sex ratio is increased relative to the rest of France with a sex odds ratio (SOR) of 1.0028, (95% CI: 1.0007, 1.0049). The detected association between municipalities' minimum distances from nuclear facilities and the sex ratio in France corroborates our findings for Germany and Switzerland.
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Affiliation(s)
- Hagen Scherb
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Computational Biology, Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany.
| | - Ralf Kusmierz
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Computational Biology, Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany.
| | - Kristina Voigt
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Computational Biology, Ingolstädter Landstr. 1, D-85764 Neuherberg, Germany.
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Douhard M, Festa-Bianchet M, Coltman DW, Pelletier F. Paternal reproductive success drives sex allocation in a wild mammal. Evolution 2016; 70:358-68. [DOI: 10.1111/evo.12860] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 01/10/2016] [Indexed: 01/08/2023]
Affiliation(s)
- Mathieu Douhard
- Département de biologie and Centre d’Études Nordiques; Université de Sherbrooke; 2500 boulevard de l'Université Sherbrooke Québec J1K 2R1 Canada
| | - Marco Festa-Bianchet
- Département de biologie and Centre d’Études Nordiques; Université de Sherbrooke; 2500 boulevard de l'Université Sherbrooke Québec J1K 2R1 Canada
| | - David W. Coltman
- Department of Biological Sciences; University of Alberta; Edmonton Alberta T6G 2E9 Canada
| | - Fanie Pelletier
- Département de biologie and Centre d’Études Nordiques; Université de Sherbrooke; 2500 boulevard de l'Université Sherbrooke Québec J1K 2R1 Canada
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Edwards AM, Cameron EZ, Pereira JC, Ferguson‐Smith MA. Paternal sex allocation: how variable is the sperm sex ratio? J Zool (1987) 2016. [DOI: 10.1111/jzo.12317] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- A. M. Edwards
- School of Biological Sciences University of Tasmania Hobart TAS Australia
- Department of Veterinary Medicine University of Cambridge Cambridge UK
| | - E. Z. Cameron
- School of Biological Sciences University of Tasmania Hobart TAS Australia
| | - J. C. Pereira
- Department of Veterinary Medicine University of Cambridge Cambridge UK
- Cytocell Ltd. Cambridge Technopark Cambridge UK
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Scherb H, Voigt K, Kusmierz R. Ionizing radiation and the human gender proportion at birth--A concise review of the literature and complementary analyses of historical and recent data. Early Hum Dev 2015; 91:841-50. [PMID: 26527392 DOI: 10.1016/j.earlhumdev.2015.10.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It has long been known that ionizing radiation causes genetic mutations and that nuclear bomb testing, nuclear accidents, and the regular and incidental emissions of nuclear facilities enhance environmental radioactivity. For this reason, the carcinogenic and genetic impact of ionizing radiation has been an escalating issue for environmental health and human health studies in the past decades. The Windscale fire (1957) and the Chernobyl accident (1986) caused alterations to the human birth sex ratio at national levels across Europe, and childhood cancer and childhood leukemia are consistently elevated near nuclear power plants. These findings are generalized and corroborated by the observation of increased sex ratios near nuclear facilities in Austria, France, Germany, Luxembourg, Switzerland, and The Netherlands. We present a concise review of the pertinent literature and we complement our review by spatiotemporal analyses of historical and most recent data. Evidence of genetic damage by elevated environmental radioactivity is provided.
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Affiliation(s)
- Hagen Scherb
- Institute of Computational Biology, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, D-85764 Neuherberg, Germany.
| | - Kristina Voigt
- Institute of Computational Biology, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, D-85764 Neuherberg, Germany
| | - Ralf Kusmierz
- Institute of Computational Biology, Helmholtz Zentrum Muenchen, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, D-85764 Neuherberg, Germany
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39
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Offspring sex in mountain goat varies with adult sex ratio but only for mothers in good condition. Behav Ecol Sociobiol 2015. [DOI: 10.1007/s00265-015-2031-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Sex-specific demography and generalization of the Trivers-Willard theory. Nature 2015; 526:249-52. [PMID: 26390152 DOI: 10.1038/nature14968] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 07/22/2015] [Indexed: 11/09/2022]
Abstract
The Trivers-Willard theory proposes that the sex ratio of offspring should vary with maternal condition when it has sex-specific influences on offspring fitness. In particular, mothers in good condition in polygynous and dimorphic species are predicted to produce an excess of sons, whereas mothers in poor condition should do the opposite. Despite the elegance of the theory, support for it has been limited. Here we extend and generalize the Trivers-Willard theory to explain the disparity between predictions and observations of offspring sex ratio. In polygynous species, males typically have higher mortality rates, different age-specific reproductive schedules and more risk-prone life history tactics than females; however, these differences are not currently incorporated into the Trivers-Willard theory. Using two-sex models parameterized with data from free-living mammal populations with contrasting levels of sex differences in demography, we demonstrate how sex differences in life history traits over the entire lifespan can lead to a wide range of sex allocation tactics, and show that correlations between maternal condition and offspring sex ratio alone are insufficient to conclude that mothers adaptively adjust offspring sex ratio.
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Santos MM, Maia LL, Nobre DM, Oliveira Neto JF, Garcia TR, Lage MCGR, de Melo MIV, Viana WS, Palhares MS, da Silva Filho JM, Santos RL, Valle GR. Sex ratio of equine offspring is affected by the ages of the mare and stallion. Theriogenology 2015; 84:1238-45. [PMID: 26234461 DOI: 10.1016/j.theriogenology.2015.07.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 06/30/2015] [Accepted: 07/01/2015] [Indexed: 11/26/2022]
Abstract
The aim of this study was to determine the influence of parental age on the sex ratio of offspring in horses. Two trials were performed. In the first trial, the data from a randomly obtained population with a 1:1 sex ratio of 59,950 Mangalarga Marchador horses born in Brazil from 1990 to 2011 were analyzed. The sex ratios of the offspring were compared among groups according to the mare and the stallion ages (from 3 to 25 years). In the first step of the analysis, the mares and stallions were grouped according to age in 5-year intervals. In the second step, the groups were based on the parental age gap at conception. In the third step, the group of the mares and stallions with similar ages from the second step was subdivided, and the different parental age subgroups that were divided into 5-year intervals were compared. In the fourth step, the sex ratio of the offspring was determined according to the ages of the mares and the stallions at conception. The second trial was based on the data from 253 horses of several breeds that were born after natural gestation into a herd from 1989 to 2010, and the offspring of groups that were younger or older than 15 years were compared. The data from both trials were analyzed using a chi-square test (P ≤ 0.01 for the first trial; and P ≤ 0.05 for the second trial) for the comparisons of the sex ratios. In the first trial, the Spearman test (P ≤ 0.01) was used to verify the correlations between the parental age and the offspring sex ratio. In the first trial, the offspring sex ratio decreased as the mare or stallion age increased, and the decrease was more marked for the mares than for the stallions. In the second trial, the mares older than 15 years had more fillies than the younger mares, but the stallion age had no effect on the sex of the offspring. The first trial, with a large number of horses, revealed the pattern of the distribution of the sex ratios of offspring according to the parental age in horses, whereas the second trial, with a more restricted number of horses, confirmed the influence of the age of the mare on the offspring sex ratio. We concluded that the parental age affected the offspring sex ratio in horses and that this effect was stronger for the mares than for the stallions.
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Affiliation(s)
- Marianna Machado Santos
- Departamento de Medicina Veterinária, Pontifícia Universidade Católica de Minas Gerais, Betim, Minas Gerais, Brazil
| | - Leonardo Lara Maia
- Departamento de Medicina Veterinária, Pontifícia Universidade Católica de Minas Gerais, Betim, Minas Gerais, Brazil
| | - Daniel Magalhães Nobre
- Escola de Medicina, Universidade Federal de Ouro Preto, Ouro Preto, Minas Gerais, Brazil
| | - José Ferraz Oliveira Neto
- Associação Brasileira dos Criadores do Cavalo Mangalarga Marchador, Belo Horizonte, Minas Gerais, Brazil
| | - Tiago Rezende Garcia
- Associação Brasileira dos Criadores do Cavalo Mangalarga Marchador, Belo Horizonte, Minas Gerais, Brazil
| | - Maria Coeli Gomes Reis Lage
- Departamento de Medicina Veterinária, Pontifícia Universidade Católica de Minas Gerais, Betim, Minas Gerais, Brazil
| | - Maria Isabel Vaz de Melo
- Departamento de Medicina Veterinária, Pontifícia Universidade Católica de Minas Gerais, Betim, Minas Gerais, Brazil
| | - Walmir Santos Viana
- Regimento de Cavalaria Alferes Tiradentes, Polícia Militar do Estado de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Maristela Silveira Palhares
- Departamento de Clínica e Cirurgia Veterinária, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - José Monteiro da Silva Filho
- Departamento de Clínica e Cirurgia Veterinária, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Renato Lima Santos
- Departamento de Clínica e Cirurgia Veterinária, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | - Guilherme Ribeiro Valle
- Departamento de Medicina Veterinária, Pontifícia Universidade Católica de Minas Gerais, Betim, Minas Gerais, Brazil.
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McPherson NO, Owens JA, Fullston T, Lane M. Preconception diet or exercise intervention in obese fathers normalizes sperm microRNA profile and metabolic syndrome in female offspring. Am J Physiol Endocrinol Metab 2015; 308:E805-21. [PMID: 25690453 DOI: 10.1152/ajpendo.00013.2015] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 02/11/2015] [Indexed: 01/11/2023]
Abstract
Obesity and type 2 diabetes are increasingly prevalent across all demographics. Paternal obesity in humans and rodents can program obesity and impair insulin sensitivity in female offspring. It remains to be determined whether these perturbed offspring phenotypes can be improved through targeted lifestyle interventions in the obese father. Using a mouse model, we demonstrate that diet or exercise interventions for 8 wk (2 rounds of spermatogenesis) in obese founder males restores insulin sensitivity and normalized adiposity in female offspring. Founder diet and/or exercise also normalizes abundance of X-linked sperm microRNAs that target genes regulating cell cycle and apoptosis, pathways central to oocyte and early embryogenesis. Additionally, obesity-associated comorbidities, including inflammation, glucose intolerance, stress, and hypercholesterolemia, were good predictors for sperm microRNA abundance and offspring phenotypes. Interventions aimed at improving paternal metabolic health during specific windows prior to conception can partially normalize aberrant epigenetic signals in sperm and improve the metabolic health of female offspring.
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Affiliation(s)
- Nicole O McPherson
- School of Paediatrics and Reproductive Health, Discipline of Obstetrics and Gynaecology, Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia; Freemasons Center for Men's Health, University of Adelaide, Adelaide, South Australia, Australia; and
| | - Julie A Owens
- School of Paediatrics and Reproductive Health, Discipline of Obstetrics and Gynaecology, Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia
| | - Tod Fullston
- School of Paediatrics and Reproductive Health, Discipline of Obstetrics and Gynaecology, Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia
| | - Michelle Lane
- School of Paediatrics and Reproductive Health, Discipline of Obstetrics and Gynaecology, Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia; Freemasons Center for Men's Health, University of Adelaide, Adelaide, South Australia, Australia; and Monash IVF Group, Melbourne, Victoria, Australia
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43
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Pluháček J, Steck BL. Different Sex Allocations in Two Related Species: The Case of the Extant Hippopotamus. Ethology 2015. [DOI: 10.1111/eth.12357] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Jan Pluháček
- Department of Ethology; Institute of Animal Science; Praha - Uhříněves Czech Republic
- Ostrava Zoo; Ostrava Czech Republic
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