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Gimeno I, Salvetti P, Carrocera S, Gatien J, Le Bourhis D, Gómez E. The recipient metabolome explains the asymmetric ovarian impact on fetal sex development after embryo transfer in cattle. J Anim Sci 2024; 102:skae081. [PMID: 38567815 PMCID: PMC11005770 DOI: 10.1093/jas/skae081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 04/02/2024] [Indexed: 04/11/2024] Open
Abstract
In cattle, lateral asymmetry affects ovarian function and embryonic sex, but the underlying molecular mechanisms remain unknown. The plasma metabolome of recipients serves to predict pregnancy after embryo transfer (ET). Thus, the aim of this study was to investigate whether the plasma metabolome exhibits distinct lateral patterns according to the sex of the fetus carried by the recipient and the active ovary side (AOS), i.e., the right ovary (RO) or the left ovary (LO). We analyzed the plasma of synchronized recipients by 1H+NMR on day 0 (estrus, n = 366) and day 7 (hours prior to ET; n = 367). Thereafter, a subset of samples from recipients that calved female (n = 50) or male (n = 69) was used to test the effects of embryonic sex and laterality on pregnancy establishment. Within the RO, the sex ratio of pregnancies carried was biased toward males. Significant differences (P < 0.05) in metabolite levels were evaluated based on the day of blood sample collection (days 0, 7 and day 7/day 0 ratio) using mixed generalized models for metabolite concentration. The most striking differences in metabolite concentrations were associated with the RO, both obtained by multivariate (OPLS-DA) and univariate (mixed generalized) analyses, mainly with metabolites measured on day 0. The metabolites consistently identified through the OPLS-DA with a higher variable importance in projection score, which allowed for discrimination between male fetus- and female fetus-carrying recipients, were hippuric acid, l-phenylalanine, and propionic acid. The concentrations of hydroxyisobutyric acid, propionic acid, l-lysine, methylhistidine, and hippuric acid were lowest when male fetuses were carried, in particular when the RO acted as AOS. No pathways were significantly regulated according to the AOS. In contrast, six pathways were found enriched for calf sex in the day 0 dataset, three for day 7, and nine for day 7/day 0 ratio. However, when the AOS was the right, 20 pathways were regulated on day 0, 8 on day 7, and 13 within the day 7/day 0 ratio, most of which were related to amino acid metabolism, with phenylalanine, tyrosine, and tryptophan biosynthesis and phenylalanine metabolism pathways being identified throughout. Our study shows that certain metabolites in the recipient plasma are influenced by the AOS and can predict the likelihood of carrying male or female embryos to term, suggesting that maternal metabolism prior to or at the time of ET could favor the implantation and/or development of either male or female embryos.
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Affiliation(s)
- Isabel Gimeno
- Animal Genetics and Reproduction, Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Centro de Biotecnología Animal, Camino de Rioseco 1225, 33394 Gijón, Spain
| | - Pascal Salvetti
- ELIANCE, Experimental facilities, Le Perroi, 37380 Nouzilly, France
| | - Susana Carrocera
- Animal Genetics and Reproduction, Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Centro de Biotecnología Animal, Camino de Rioseco 1225, 33394 Gijón, Spain
| | - Julie Gatien
- ELIANCE, Experimental facilities, Le Perroi, 37380 Nouzilly, France
| | | | - Enrique Gómez
- Animal Genetics and Reproduction, Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Centro de Biotecnología Animal, Camino de Rioseco 1225, 33394 Gijón, Spain
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2
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Evidence that Murciano-Granadina does with longer anogenital distance are more fertile and prolific and produce heavier and male-biased litters. Anim Reprod Sci 2022; 244:107047. [DOI: 10.1016/j.anireprosci.2022.107047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 06/13/2022] [Accepted: 07/24/2022] [Indexed: 11/17/2022]
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3
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Naidu SJ, Arangasamy A, Selvaraju S, Binsila BK, Reddy IJ, Ravindra JP, Bhatta R. Maternal influence on the skewing of offspring sex ratio: a review. ANIMAL PRODUCTION SCIENCE 2022. [DOI: 10.1071/an21086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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4
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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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5
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Xie Y, Xu Z, Wu Z, Hong L. Sex Manipulation Technologies Progress in Livestock: A Review. Front Vet Sci 2020; 7:481. [PMID: 32923466 PMCID: PMC7456994 DOI: 10.3389/fvets.2020.00481] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 06/29/2020] [Indexed: 12/14/2022] Open
Abstract
Sex manipulation technologies allow predetermination of the sex of animal offspring by altering the normal reproductive process. In livestock production, the difference in type and gender can translate into significant economic benefits, including alleviation of severe food shortages. In livestock, however, the commercial application of sex manipulation technologies is currently available for cattle only. In this review, we described the brief history of sex manipulation, and the research progresses of common methods used in sex manipulation thus far. Information presented in this review can inform future studies on expanding the scope and use of sex manipulation technologies in livestock.
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Affiliation(s)
- Yanshe Xie
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Lingnan Guangdong Laboratory of Modern Agriculture, Guangzhou, China
| | - Zhiqian Xu
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Lingnan Guangdong Laboratory of Modern Agriculture, Guangzhou, China
| | - Zhenfang Wu
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Lingnan Guangdong Laboratory of Modern Agriculture, Guangzhou, China
| | - Linjun Hong
- Guangdong Provincial Key Laboratory of Agro-Animal Genomics and Molecular Breeding, National Engineering Research Center for Breeding Swine Industry, College of Animal Science, South China Agricultural University, Guangzhou, China.,Lingnan Guangdong Laboratory of Modern Agriculture, Guangzhou, China
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6
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Raval NP, Shah TM, George LB, Joshi CG. Effect of the pH in the enrichment of X or Y sex chromosome-bearing sperm in bovine. Vet World 2019; 12:1299-1303. [PMID: 31641311 PMCID: PMC6755399 DOI: 10.14202/vetworld.2019.1299-1303] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 07/05/2019] [Indexed: 12/26/2022] Open
Abstract
Background and Aim: Studies have shown that the pH of the vagina during the course of fertilization may influence the migration of X- and Y-bearing spermatozoa and thus leading to skewness in the sex of the offspring. Hence, this study was carried out to check the effect of the pH in the enrichment of X or Y sex chromosome-bearing sperm in bovine (Bos indicus). Materials and Methods: To check the effect of pH in the enrichment of X or Y sex chromosome-bearing sperm in bovine, we used buffers of various pH ranging from 5.5 to 9.0 for swim-up procedure of sperm sample and collected upper and bottom fraction from the same buffer and checked the abundance of X- and Y-bearing spermatozoa by droplet digital polymerase chain reaction using X- and Y-chromosome-specific DNA probe. Results: The abundance of X- and Y-bearing spermatozoa was not differed significantly in either of the fraction collected. Conclusion: Thus, it appears to be unlikely that an immediate impact of pH on sperm can be a solitary impact on the sex of offspring in bovine.
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Affiliation(s)
- Nidhi P Raval
- Department of Animal Biotechnology, College of Veterinary Science and Animal Husbandry, Anand Agricultural University, Anand, Gujarat, India.,Department of Zoology, Biomedical Technology and Human Genetics, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, India
| | - Tejas M Shah
- Department of Animal Biotechnology, College of Veterinary Science and Animal Husbandry, Anand Agricultural University, Anand, Gujarat, India
| | - Linz-Buoy George
- Department of Zoology, Biomedical Technology and Human Genetics, University School of Sciences, Gujarat University, Ahmedabad, Gujarat, India
| | - Chaitanya G Joshi
- Gujarat Biotechnology Research Centre, Block B and D, 6 Floor, MS Building, Sector - 11, Gandhinagar, Gujarat, India
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7
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Fishman R, Vortman Y, Shanas U, Koren L. Non-model species deliver a non-model result: Nutria female fetuses neighboring males in utero have lower testosterone. Horm Behav 2019; 111:105-109. [PMID: 30790563 DOI: 10.1016/j.yhbeh.2019.02.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/06/2019] [Accepted: 02/14/2019] [Indexed: 12/15/2022]
Abstract
Neighboring fetuses may impact their siblings in various respects, depending on their in utero location and sex. The effects of the intrauterine position (IUP) are widely studied in model organisms, especially laboratory bred murine strains that are characterized by short gestations and altricial offspring. In some species, the proximity to a male fetus and its higher circulating testosterone masculinizes neighboring female fetuses. In utero testosterone exposure might be manifested as higher testosterone concentrations, which contribute to a variation in morphology, reproductive potential and behavior. In this study, we examined the influence of neighboring an opposite sex fetus on testosterone levels in a feral animal model characterized by a long gestation and precocious offspring. Using necropsies of culled nutria (Myocastor coypus), we accurately determined the IUP and quantified testosterone immunoreactivity in fetal hair. We found that as expected, both male and female fetuses neighboring a male in utero had longer anogenital distance. However, females adjacent to males in utero showed lower testosterone levels than male fetuses, while testosterone levels of females without a male neighbor did not differ from those of males. This surprising result suggests an alternative mode by which local exogenous steroids may modify the local fetal environment. Our study emphasizes the importance of examining known phenomena in species with different life histories, other than the traditional murine models, to enhance our understanding of the evolutionary mechanisms that are driving sexual differentiation.
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Affiliation(s)
- Ruth Fishman
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Yoni Vortman
- Hula Research Center, Department of Animal Sciences, Tel-Hai College, Upper Galilee 1220800, Israel
| | - Uri Shanas
- Faculty of Life Sciences, University of Haifa-Oranim, Tivon 3600600, Israel
| | - Lee Koren
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel.
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8
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Female-biased sex ratios are associated with higher maternal testosterone levels in nutria (Myocastor coypus). Behav Ecol Sociobiol 2018. [DOI: 10.1007/s00265-018-2517-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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9
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Seyfang J, Kirkwood RN, Tilbrook AJ, Ralph CR. The sex ratio of a gilt’s birth litter can affect her fitness as a breeding female. ANIMAL PRODUCTION SCIENCE 2018. [DOI: 10.1071/an17192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Lifetime reproductive performance and behaviour are established in utero driven by genetics and the steroidal milieu of the uterine environment. Developing males synthesise androgens that can be absorbed by females in the litter. Consequently, the proportion of males in a litter has the potential to affect both lifetime reproductive performance and behaviour of female littermates. Although reproductive potential is understandably important for gilt selection, behaviour is becoming progressively more important as group housing of sows increases. Aggression can be a cause for removal from the breeding herd, and can also negatively affect reproductive performance and herd longevity. This review covers existing evidence of masculinisation in rodents and sheep, the mechanism causing masculinisation, and the knowledge gaps surrounding masculinisation in pigs. Premature culling of gilts is an economic and animal welfare issue in the pork industry resulting in low retention of gilts and reduced productivity. The selection of gilts needs to be improved to incorporate both lifetime reproductive potential and behaviour. We determined that there is cause to investigate the effect of the birth litter sex ratio of a gilt on her suitability for selection into the breeding herd.
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10
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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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11
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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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12
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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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13
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Kim TB, Oh JK, Kim KT, Yoon SJ, Kim SW. Does the Mother or Father Determine the Offspring Sex Ratio? Investigating the Relationship between Maternal Digit Ratio and Offspring Sex Ratio. PLoS One 2015; 10:e0143054. [PMID: 26575995 PMCID: PMC4648576 DOI: 10.1371/journal.pone.0143054] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 10/30/2015] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE In mammals, high parental testosterone levels present around the time of conception are thought to skew offspring sex ratio toward sons. The second to fourth digit ratio (digit ratio) is now widely accepted as a negative correlate of prenatal testosterone. Thus, we investigated the association between digit ratio and offspring sex ratio. METHODS A total of 508 Korean patients (257 males and 251 females) less than 60 years old who had one or more offspring were prospectively enrolled. The lengths of the 2nd and 4th digits of the right hand were measured by a single investigator using a digital vernier calliper. Next, the patients' lifetime offspring birth sex ratios were investigated. RESULTS Maternal (rather than paternal) digit ratio was significantly associated with the number of sons (r = -0.153, p = 0.015), number of daughters (r = 0.130, p = 0.039), and offspring sex ratio (r = -0.171, p = 0.007). And, the maternal digit ratio was a significant factor for predicting offspring sex ratio (B = -1.620, p = 0.008) on multiple linear regression analysis. The female patients with a lower digit ratio (< 0.95) were found to have a higher offspring sex ratio (0.609 versus 0.521, p = 0.046) compared to those with a higher digit ratio (≥ 0.95). Furthermore, females in the low digit ratio group have a probability 1.138 greater of having sons than females in the high digit ratio group. CONCLUSIONS Maternal digit ratio was negatively associated with offspring sex ratio. Females with a lower digit ratio were more likely to have more male offspring compared to those with a higher digit ratio. Thus, our results suggest that the sex of offspring might be more influenced by maternal rather than paternal factors.
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Affiliation(s)
- Tae Beom Kim
- Department of Urology, Gachon University Gil Hospital, Incheon, Republic of Korea
| | - Jin Kyu Oh
- Department of Urology, Gachon University Gil Hospital, Incheon, Republic of Korea
| | - Kwang Taek Kim
- Department of Urology, Gachon University Gil Hospital, Incheon, Republic of Korea
| | - Sang Jin Yoon
- Department of Urology, Gachon University Gil Hospital, Incheon, Republic of Korea
| | - Soo Woong Kim
- Department of Urology, Seoul National University Hospital, Seoul, Republic of Korea
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14
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Rezagholizadeh A, Gharagozlou F, Akbarinejad V, Youssefi R. Left-Sided Ovulation Favors More Male Foals Than Right-Sided Ovulation in Thoroughbred Mares. J Equine Vet Sci 2015. [DOI: 10.1016/j.jevs.2014.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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15
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Schnettler S, Klüsener S. Economic stress or random variation? Revisiting German reunification as a natural experiment to investigate the effect of economic contraction on sex ratios at birth. Environ Health 2014; 13:117. [PMID: 25533777 PMCID: PMC4391084 DOI: 10.1186/1476-069x-13-117] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 12/04/2014] [Indexed: 06/04/2023]
Abstract
BACKGROUND The economic stress hypothesis (ESH) predicts decreases in the sex ratio at birth (SRB) following economic decline. However, as many factors influence the SRB, this hypothesis is difficult to test empirically. Thus, researchers make use of quasi-experiments such as German reunification: The economy in East, but not in West Germany, underwent a rapid decline in 1991. A co-occurrence of a decline in the East German SRB in 1991 has been interpreted by some as support for the ESH. However, another explanation might be that the low SRB in 1991 stems from increased random variation in the East German SRB due to a drastically reduced number of births during the crisis. We look into this alternative random variation hypothesis (RVH) by re-examining the German case with more detailed data. METHODS Our analysis has two parts. First, using aggregate-level birth register data for all births in the period between 1946 and 2011, we plot the quantum and variance of the SRB and the number of births and unemployment rates, separately for East and West Germany, and conduct a time series analysis on the East German SRB over time. Second, we model the odds for a male birth at the individual level in a multiple logistic regression (1991-2010, ~13.9 million births). Explanatory variables are related to the level of the individual birth, the mother of the child born, and the regional economic context. RESULTS The aggregate-level analysis reveals a higher degree of variation of the SRB in East Germany. Deviations from the time trend occur in several years, seemingly unrelated to economic development, and the deviation in 1991 is not statistically significant. The individual-level analysis confirms that the 1991-drop in the East German SRB cannot directly be attributed to economic development and that there is no statistically significant effect of economic development on sex determination in East or West Germany. CONCLUSION Outcomes support the RVH but not the ESH. Furthermore, our results speak against a statistically significant effect of the reunification event itself on the East German SRB. We discuss the relative importance of behavioral and physiological responses to macro-level stressors, a distinction that may help integrate previously mixed findings.
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Affiliation(s)
- Sebastian Schnettler
- Department of Sociology, University of Konstanz, Box 40, Universitätsstr. 10, 78457, Konstanz, Germany.
| | - Sebastian Klüsener
- Max Planck Institute for Demographic Research, Konrad-Zuse-Str. 1, 18057, Rostock, Germany.
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Trigal B, Díez C, Muñoz M, Caamaño JN, Goyache F, Correia-Alvarez E, Corrales FJ, Mora MI, Carrocera S, Martin D, Gómez E. Elements of functional genital asymmetry in the cow. Reprod Fertil Dev 2014; 26:493-501. [PMID: 24709319 DOI: 10.1071/rd13056] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 03/11/2013] [Indexed: 11/23/2022] Open
Abstract
Asymmetry in the cow affects ovarian function and pregnancy. In this work we studied ovarian and uterine asymmetry. Synchronised animals, in which in vitro-produced embryos (n=30-60) had been transferred on Day 5 to the uterine horn ipsilateral to the corpus luteum (CL), were flushed on Day 8. Ovulatory follicle diameter, oestrus response and total protein flushed did not differ between sides. However, a corpus luteum in the right ovary led to plasma progesterone concentrations that were higher than when it was present in the left ovary. Fewer embryos were recovered from the left than the right horn. Among 60 uterine proteins identified by difference gel electrophoresis, relative abundance of nine (acyl-CoA dehydrogenase, very long chain; twinfilin, actin-binding protein, homologue 1; enolase 1; pyruvate kinase isozymes M1/M2 (rabbit); complement factor B Bb fragment ; albumin; fibrinogen gamma-B chain; and ezrin differed (P<0.05) between horns. Glucose concentration was higher, and fructose concentration lower, in the left horn. In a subsequent field trial, pregnancy rates after embryo transfer did not differ between horns (51.0±3.6, right vs 53.2±4.7, left). However, Day 7 blood progesterone concentrations differed (P=0.018) between pregnant and open animals in the left (15.9±1.7 vs 8.3±1.2) but not in the right horn (12.4±1.3 vs 12.4±1.2). Progesterone effects were independent of CL quality (P=0.55). Bilateral genital tract asymmetry in the cow affects progesterone, proteins and hexoses without altering pregnancy rates.
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Affiliation(s)
- B Trigal
- Centro de Biotecnología Animal, SERIDA, Camino de Rioseco 1225, 33394 Gijón, Spain
| | - C Díez
- Centro de Biotecnología Animal, SERIDA, Camino de Rioseco 1225, 33394 Gijón, Spain
| | - M Muñoz
- Centro de Biotecnología Animal, SERIDA, Camino de Rioseco 1225, 33394 Gijón, Spain
| | - J N Caamaño
- Centro de Biotecnología Animal, SERIDA, Camino de Rioseco 1225, 33394 Gijón, Spain
| | - F Goyache
- Centro de Biotecnología Animal, SERIDA, Camino de Rioseco 1225, 33394 Gijón, Spain
| | - E Correia-Alvarez
- Centro de Biotecnología Animal, SERIDA, Camino de Rioseco 1225, 33394 Gijón, Spain
| | - F J Corrales
- Centro de Investigación Médica Aplicada (CIMA), Avda Pío XII 55, 31008 Pamplona, Navarra, Spain
| | - M I Mora
- Centro de Investigación Médica Aplicada (CIMA), Avda Pío XII 55, 31008 Pamplona, Navarra, Spain
| | - S Carrocera
- Centro de Biotecnología Animal, SERIDA, Camino de Rioseco 1225, 33394 Gijón, Spain
| | - D Martin
- Centro de Biotecnología Animal, SERIDA, Camino de Rioseco 1225, 33394 Gijón, Spain
| | - E Gómez
- Centro de Biotecnología Animal, SERIDA, Camino de Rioseco 1225, 33394 Gijón, Spain
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17
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Ryan CP, Anderson WG, Berkvens CN, Hare JF. Maternal gestational cortisol and testosterone are associated with trade-offs in offspring sex and number in a free-living rodent (Urocitellus richardsonii). PLoS One 2014; 9:e111052. [PMID: 25353347 PMCID: PMC4213000 DOI: 10.1371/journal.pone.0111052] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 09/26/2014] [Indexed: 11/30/2022] Open
Abstract
The adaptive manipulation of offspring sex and number has been of considerable interest to ecologists and evolutionary biologists. The physiological mechanisms that translate maternal condition and environmental cues into adaptive responses in offspring sex and number, however, remain obscure. In mammals, research into the mechanisms responsible for adaptive sex allocation has focused on two major endocrine axes: the hypothalamic pituitary adrenal (HPA) axis and glucocorticoids, and the hypothalamic pituitary gonadal (HPG) axis and sex steroids, particularly testosterone. While stress-induced activation of the HPA axis provides an intuitive model for sex ratio and litter size adjustment, plasma glucocorticoids exist in both bound and free fractions, and may be acting indirectly, for example by affecting plasma glucose levels. Furthermore, in female mammals, activation of the HPA axis stimulates the secretion of adrenal testosterone in addition to glucocorticoids (GCs). To begin to untangle these physiological mechanisms influencing offspring sex and number, we simultaneously examined fecal glucocorticoid metabolites, free and bound plasma cortisol, free testosterone, and plasma glucose concentration during both gestation and lactation in a free-living rodent (Urocitellus richardsonii). We also collected data on offspring sex and litter size from focal females and from a larger study population. Consistent with previous work in this population, we found evidence for a trade-off between offspring sex and number, as well as positive and negative correlations between glucocorticoids and sex ratio and litter size, respectively, during gestation (but not lactation). We also observed a negative relationship between testosterone and litter size during gestation (but not lactation), but no effect of glucose on either sex ratio or litter size. Our findings highlight the importance of binding proteins, cross-talk between endocrine systems, and temporal windows in the regulation of trade-offs in offspring sex and number.
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Affiliation(s)
- Calen P. Ryan
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
- * E-mail:
| | - W. Gary Anderson
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | | | - James F. Hare
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
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18
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Emadi SR, Rezaei A, Bolourchi M, Hovareshti P, Akbarinejad V. Administration of estradiol benzoate before insemination could skew secondary sex ratio toward males in Holstein dairy cows. Domest Anim Endocrinol 2014; 48:110-8. [PMID: 24906936 DOI: 10.1016/j.domaniend.2014.03.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 03/05/2014] [Accepted: 03/05/2014] [Indexed: 11/21/2022]
Abstract
The present study was conducted to investigate the effect of estradiol benzoate administration before insemination on secondary sex ratio (proportion of male calves at birth) in Holstein dairy cows. Cows (n = 1,647) were randomly assigned to 2 experimental groups by parity over a 1-yr period. Cows in the control group (n = 827; 232 primiparous and 595 multiparous cows) received 2 administrations of PGF2α (500 μg) 14 d apart, started at 30 to 35 d postpartum. Twelve d after the second PGF2α injection, cows received GnRH (100 μg), followed by administration of PGF2α 7 d later. Cows in the treatment group (n = 820; 238 primiparous and 582 multiparous cows) received the same hormonal administrations as the cows in the control group. Additionally, cows in the treatment group received estradiol benzoate (1 mg) 1 d after the third PGF2α injection. Estrus detection by visual observation was started 1 d after the third PGF2α injection and after estradiol administration in the control (for 6 d) and treatment (for 36 h) groups, respectively. Artificial insemination was carried out 12 h after observation of standing estrus. Exposure of cows to heat stress at conception was determined based on temperature-humidity index. Estrus detection rate was lower in primiparous than in multiparous cows (P < 0.05), but conception rate was higher in primiparous vs multiparous cows (P < 0.05). Estradiol administration improved estrus detection rate and fertility (P < 0.05); moreover, it increased secondary sex ratio (adjusted odds ratio: 1.645; P = 0.017). Exposure to heat stress diminished heat detection rate and fertility (P < 0.05), and altered secondary sex ratio toward males (adjusted odds ratio: 2.863; P = 0.012). In conclusion, the present study revealed that estradiol administration before insemination could improve fertility and increase the probability of calves being male in Holstein dairy cows. Moreover, the results showed that cows exposed to heat stress around conception had diminished fertility and increased secondary sex ratio.
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Affiliation(s)
- S R Emadi
- Department of Theriogenology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran; Theriogenology Association, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - A Rezaei
- Department of Theriogenology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - M Bolourchi
- Department of Theriogenology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - P Hovareshti
- Department of Theriogenology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - V Akbarinejad
- Young Researchers and Elites Club, North Tehran Branch, Islamic Azad University, Tehran, Iran.
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Gharagozlou F, Vojgani M, Akbarinejad V, Niasari-Naslaji A, Hemmati M, Youssefi R. Parallel distribution of sexes within left and right uterine horns in Holstein dairy cows: Evidence that the effect of side of pregnancy on sex ratio could be breed-specific in cattle. Anim Reprod Sci 2013; 142:101-5. [DOI: 10.1016/j.anireprosci.2013.09.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 09/22/2013] [Accepted: 09/30/2013] [Indexed: 11/17/2022]
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20
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Evolution and the variation of mammalian sex ratios at birth: Reflections on Trivers and Willard (1973). J Theor Biol 2013; 334:141-8. [DOI: 10.1016/j.jtbi.2013.06.023] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 06/12/2013] [Accepted: 06/20/2013] [Indexed: 11/21/2022]
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21
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Szenczi P, Bánszegi O, Groó Z, Altbäcker V. Anogenital distance and condition as predictors of litter sex ratio in two mouse species: a study of the house mouse (Mus musculus) and mound-building mouse (Mus spicilegus). PLoS One 2013; 8:e74066. [PMID: 24069268 PMCID: PMC3777973 DOI: 10.1371/journal.pone.0074066] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 07/30/2013] [Indexed: 11/23/2022] Open
Abstract
The Trivers - Willard hypothesis (1973) suggests that the maternal condition may affect the female's litter size and sex ratio. Since then other factors had been found. Previous findings revealed in the case of some mammalian species, that females with larger anogenital distance have smaller litters, while the sex ratio is male-biased. That has only been demonstrated in laboratory animals, while the genetic diversity of a wild population could mask the phenomenon seen in laboratory colonies. We examined the connection between morphological traits (weight and anogenital distance) and the reproductive capacity of two wild mice species, the house mouse and the mound-building mice. We showed in both species that anogenital distance and body weight correlated positively in pre-pubertal females, but not in adults. Neither the house mouse nor the mound-building mouse mothers' weight had effect on their litter's size and sex ratio. Otherwise connection was found between the mothers' anogenital distance and their litters' sex ratio in both species. The results revealed that females with larger anogenital distance delivered male biased litter in both species. The bias occurred as while the number of female pups remained the same; mothers with large anogenital distance delivered more male pups compared to the mothers with small anogenital distance. We concluded that a female's prenatal life affects her reproductive success more than previously anticipated.
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Affiliation(s)
- Péter Szenczi
- Department of Ethology, Eötvös Loránd University, Göd, Hungary
| | - Oxána Bánszegi
- Institute for Soil Sciences and Agricultural Chemistry, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary
| | - Zita Groó
- Department of Ethology, Eötvös Loránd University, Göd, Hungary
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Cognitive ability correlates positively with son birth and predicts cross-cultural variation of the offspring sex ratio. Naturwissenschaften 2013; 100:559-69. [DOI: 10.1007/s00114-013-1052-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2012] [Revised: 04/18/2013] [Accepted: 04/19/2013] [Indexed: 11/30/2022]
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Macaulay AD, Hamilton CK, King WA, Bartlewski PM. Influence of physiological concentrations of androgens on the developmental competence and sex ratio of in vitro produced bovine embryos. Reprod Biol 2013; 13:41-50. [DOI: 10.1016/j.repbio.2013.01.175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 11/05/2012] [Indexed: 10/27/2022]
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Schnettler S. Revisiting a sample of U.S. billionaires: how sample selection and timing of maternal condition influence findings on the Trivers-Willard effect. PLoS One 2013; 8:e57446. [PMID: 23437389 PMCID: PMC3578789 DOI: 10.1371/journal.pone.0057446] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Accepted: 01/23/2013] [Indexed: 11/18/2022] Open
Abstract
Based on evolutionary theory, Trivers & Willard (TW) predicted the existence of mechanisms that lead parents with high levels of resources to bias offspring sex composition to favor sons and parents with low levels of resources to favor daughters. This hypothesis has been tested in samples of wealthy individuals but with mixed results. Here, I argue that both sample selection due to a high number of missing cases and a lacking specification of the timing of wealth accumulation contribute to this equivocal pattern. This study improves on both issues: First, analyses are based on a data set of U.S. billionaires with near-complete information on the sex of offspring. Second, subgroups of billionaires are distinguished according to the timing when they acquired their wealth. Informed by recent insights on the timing of a potential TW effect in animal studies, I state two hypotheses. First, billionaires have a higher share of male offspring than the general population. Second, this effect is larger for heirs and heiresses who are wealthy at the time of conception of all of their children than for self-made billionaires who acquired their wealth during their adult lives, that is, after some or all of their children have already been conceived. Results do not support the first hypothesis for all subgroups of billionaires. But for males, results are weakly consistent with the second hypothesis: Heirs but not self-made billionaires have a higher share of male offspring than the U.S. population. Heiresses, on the other hand, have a much lower share of male offspring than the U.S. average. This hints to a possible interplay of at least two mechanisms affecting sex composition. Implications for future research that would allow disentangling the distinct mechanisms are discussed.
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James WH. Hypotheses on the stability and variation of human sex ratios at birth. J Theor Biol 2012; 310:183-6. [DOI: 10.1016/j.jtbi.2012.06.038] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Revised: 06/13/2012] [Accepted: 06/28/2012] [Indexed: 11/26/2022]
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Helle S, Laaksonen T, Huitu O. Sex-specific offspring growth according to maternal testosterone, corticosterone, and glucose levels. Behav Ecol 2012. [DOI: 10.1093/beheco/ars155] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Parental status and gender preferences for children: is differential fertility stopping consistent with the trivers-willard hypothesis? J Biosoc Sci 2012; 45:683-704. [PMID: 22989525 DOI: 10.1017/s0021932012000557] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Based on evolutionary reasoning, Trivers & Willard (1973) predicted status-biased sex composition and parental investment with son-preferencing effects in higher, and daughter-preferencing effects in lower status groups. Previous research shows mixed results. This study uses event-history methods and Swedish register data to study one possible mechanism in isolation: do parents in different status groups vary in their proclivities to continue fertility based on the sex composition of previous offspring? The results show no support for the Trivers-Willard hypothesis on a wide range of different status indicators. Future research on the stated hypothesis should focus on physiological rather than behavioural mechanisms.
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28
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James WH. The relevance of the epidemiology of human sex ratios at birth to some medical problems. Paediatr Perinat Epidemiol 2012; 26:181-9. [PMID: 22471677 DOI: 10.1111/j.1365-3016.2012.01267.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The human sex ratio (proportion male at birth) shows considerable variation which is central to reproductive epidemiology. For example, it has reportedly shown significant secular trends and wartime variation, and it has shown replicated variation with parental exposure to several deleterious chemicals. However, scientific progress in identifying the causes of these forms of variation has been very slow and, as described here, this has elicited some scepticism. Benefits may be expected from identifying these causes. Two (non-competing) hypotheses have emerged, the first relating to the hormonal regulation of sex ratio at conception, and the second to the sex-selective effects of stressors during pregnancy. It is shown here that if the first of these hypotheses was substantially correct, it would illuminate a number of scientific and medical problems, for example, the causes of autism and of selected sex-related congenital malformations and obstetric pathologies.
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Affiliation(s)
- William H James
- Department of Genetics, Evolution and Environment, University College London, London, UK.
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29
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Ryan CP, Anderson WG, Gardiner LE, Hare JF. Stress-induced sex ratios in ground squirrels: support for a mechanistic hypothesis. Behav Ecol 2011. [DOI: 10.1093/beheco/arr169] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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30
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Grant VJ, Konečná M, Sonnweber RS, Irwin RJ, Wallner B. Macaque mothers’ preconception testosterone levels relate to dominance and to sex of offspring. Anim Behav 2011. [DOI: 10.1016/j.anbehav.2011.07.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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31
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THE CATEGORIES OF EVIDENCE RELATING TO THE HYPOTHESIS THAT MAMMALIAN SEX RATIOS AT BIRTH ARE CAUSALLY RELATED TO THE HORMONE CONCENTRATIONS OF BOTH PARENTS AROUND THE TIME OF CONCEPTION. J Biosoc Sci 2010; 43:167-84. [DOI: 10.1017/s0021932010000660] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SummaryThis note categorizes the evidence for the hypothesis that mammalian offspring sex ratios (proportions male) are causally related to the hormone levels of both parents around the time of conception. Most of the evidence may be acknowledged to be correlational and observational. As such it might be suspected of having been selected; or of having been subject to other forms of bias or confounding; or, at any rate, of being inadequate as a firm basis for causal inference. However, there are other types of evidence that are not vulnerable to these types of criticism. These are from the following sources: (1) previously neglected data from Nazi Germany and Soviet Russia; (2) fulfilled predictions; (3) genetics; and (4) a network of logically (mathematically) related propositions, for some of which there is overwhelming empirical evidence. It is suggested that this variety of evidence confers greater overall credibility on the hypothesis than would be the case if all the evidence were of the same observational/correlational status. This observational/correlational evidence is tabulated to illustrate its consistency.
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Grant VJ, Chamley LW. Can mammalian mothers influence the sex of their offspring peri-conceptually? Reproduction 2010; 140:425-33. [PMID: 20591970 DOI: 10.1530/rep-10-0137] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Although controversial, growing evidence from evolutionary biology suggests that the mammalian mother may have a role in influencing the sex of her offspring. However, there is competing information on the molecular mechanisms by which such influence could be manifested. The new initiatives are based on hypotheses from evolutionary biology: the 'good condition' hypothesis, which suggests that post conception, higher levels of maternal glucose may differentially promote the development of male embryos; and the 'maternal dominance' hypothesis, which proposes that before conception, higher follicular testosterone may influence the development of the ovum so that it emerges already adapted to receive an X- or a Y-chromosome-bearing spermatozoon. Now, it seems these hypothesised mechanisms could be operating in synchrony, each complementing and reinforcing the other. On the other hand, there are continuing problems in identifying a precise sequence of mechanisms as evidenced from research in sperm-sorting. Research on high-fat diets and the sex ratio in polytocous species may indicate important differences in proximate mechanisms for sex allocation between polytocous and monotocous mammals.
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Affiliation(s)
- Valerie J Grant
- Department of Psychological Medicine Department of Obstetrics and Gynaecology, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
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33
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Navara KJ. Programming of offspring sex ratios by maternal stress in humans: assessment of physiological mechanisms using a comparative approach. J Comp Physiol B 2010; 180:785-96. [PMID: 20544204 DOI: 10.1007/s00360-010-0483-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 05/18/2010] [Accepted: 05/20/2010] [Indexed: 01/23/2023]
Abstract
Sex ratio adjustment has become a hot topic in ecology and evolutionary biology, as documentations of sex ratio skews are numerous, and include examples in diverse animal species. Over the past several decades, scientists have repeatedly debated whether human sex ratios also significantly deviate toward one sex or the other based on environmental or social conditions. An increasing number of studies supports the idea that exposure to stressful conditions can influence the sexes of offspring produced by humans, a majority of which document significantly fewer males after exposure to adverse conditions such as severe life events, economic disruption, or natural disasters. From a comparative standpoint, these findings are similar to studies in non-human mammals and other vertebrate species showing a bias toward females during times of stress. However, the mechanisms by which stress-related biases in the offspring sex ratio may occur remain elusive, and the involvement of glucocorticoids indicating a true influence of stress itself remains unstudied. Here, I review the evidence that stressful events induce sex ratio adjustment in humans. Additionally, I discuss the possibility for glucocorticoid mediation of sex ratio adjustment and the potential reproductive stages during which stress-induced sex ratio adjustment may occur in humans and other mammals.
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Affiliation(s)
- Kristen J Navara
- Department of Poultry Science, The University of Georgia, 203 Poultry Science Building, 110 Cedar Street, Athens, GA 30605, USA.
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34
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García-Herreros M, Bermejo-Álvarez P, Rizos D, Gutiérrez-Adán A, Fahey AG, Lonergan P. Intrafollicular testosterone concentration and sex ratio in individually cultured bovine embryos. Reprod Fertil Dev 2010; 22:533-8. [DOI: 10.1071/rd09157] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Accepted: 09/17/2009] [Indexed: 11/23/2022] Open
Abstract
Recent studies have suggested a relationship between bovine follicular fluid testosterone concentration and the likelihood of the oocyte being fertilised by an X- or Y-bearing spermatozoon; however, this theory has been challenged. To further test this hypothesis, follicles were dissected from the ovaries of slaughtered heifers, measured and carefully ruptured. The cumulus–oocyte complex (COC) was removed and the follicular fluid collected and testosterone concentration determined by radioimmunoassay. COCs were matured, fertilised and cultured in an individually identifiable manner; all cleaved embryos (2- to 4-cell stage, n = 164) had their sex determined by PCR. Testosterone concentrations were positively skewed. There was no significant difference between follicular fluid testosterone concentrations in male and female embryos (mean ± s.e.m. 51.5 ± 5.59 and 49.5 ± 7.42 ng mL–1, respectively). Linear, quadratic and cubic logistical regression showed that follicular testosterone concentration could not reliably predict the sex of the embryo with odds ratios of 1.001, 1.013 and 1.066, repectively, and coefficient of determination (R2) values of 0.0003, 0.0126 and 0.0567, respectively. Follicular size and testosterone concentration were not related (R2 = 0.087). Finally, follicular size had no influence on embryo sex determination (P = 0.70). In conclusion, under the conditions of the present study, the likelihood of an oocyte being fertilised by an X- or Y-bearing spermatozoon was not affected by the size of the follicle from which it was derived, nor by the testosterone concentration in the follicular fluid.
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35
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Rodríguez PEA, Sanchez MS. Maternal exposure to triclosan impairs thyroid homeostasis and female pubertal development in Wistar rat offspring. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2010; 73:1678-88. [PMID: 21058171 DOI: 10.1080/15287394.2010.516241] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Although the effects of triclosan have been examined in male reproductive functions, it is unknown whether this potent antibacterial agent affects pregnancy and female pubertal development. Effects of maternal exposure to triclosan on thyroid homeostasis (TH) and reproductive-tract development in female Wistar rats were thus studied. Dams were exposed daily to triclosan (0, 1, 10, or 50 mg/kg/d) from 8 d before mating to lactation day 21. Offspring were also exposed after weaning. In vivo triclosan estrogenic activity was screened by uterotrophic assay and vaginal opening (VO), with first estrus and uterus and ovarian weight determined in offspring. Dam blood samples were taken during pregnancy and lactation to examine the effect of triclosan on TH. No apparent external signs of toxicity or differences in mean numbers of implantation sites were observed in treated rats. Triclosan treatment decreased total serum T(4) and T(3) in pregnant rats and also lowered sex ratio, lowered pup body weights on postnatal day (PND) 20, and delayed VO in offspring. In addition, the highest dose of triclosan significantly reduced the live birth index (percentage) and 6-d survival index. Data indicate that triclosan impairs thyroid homeostasis and reproductive toxicity in adult rats and produces fetal toxicity in offspring exposed in utero, during lactation, and after weaning.
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Affiliation(s)
- Pablo E A Rodríguez
- Subsecretaria CEPROCOR, Ministerio de Ciencia y Tecnologia, Cordoba, Argentina
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36
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Grant VJ. Wartime sex ratios: Stress, male vulnerability and the interpretation of atypical sex ratio data. ACTA ACUST UNITED AC 2009. [DOI: 10.1556/jep.7.2009.4.5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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37
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Díez C, Bermejo-Alvarez P, Trigal B, Caamaño JN, Muñoz M, Molina I, Gutiérrez-Adán A, Carrocera S, Martín D, Gómez E. Changes in testosterone or temperature during the in vitro oocyte culture do not alter the sex ratio of bovine embryos. ACTA ACUST UNITED AC 2009; 311:448-52. [PMID: 19384917 DOI: 10.1002/jez.540] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
High follicular testosterone levels have been associated with a skew in the sex ratio in favor of males following in vitro fertilization, whereas egg incubation temperature has been found to influence sex ratio in some reptiles. The incubation temperature interferes with the aromatase activity, resulting in a sex determination mechanism thought to be lost in mammals. In this work we aimed to test the effects of testosterone on sex ratio of bovine embryos produced in vitro and to determine whether effects of sex and temperature are effectively decoupled in mammals. Bovine oocytes were in vitro matured for 22 hr in TCM199, PVA, FSH and LH after a 22 hr meiotic arrest in TCM199, PVA and roscovitine 25 microM. Matured oocytes were in vitro fertilized and cultured up to Day 3, and embryos having three or more cells were sexed. In the first experiment, testosterone (0, 30, 300 and 1,500 nM), present both during meiotic inhibition and subsequent in vitro maturation (IVM), did not affect development rates or embryonic sex ratio. In the second experiment, increasing incubation temperatures (38, 39 or 40 degrees C) during meiotic inhibition and subsequent IVM, reduced embryo development, but did not change the sex ratio. Under our experimental conditions, testosterone does not promote a preferential selection of Y-chromosome bearing spermatozoa by the oocyte, and temperature and sex ratio seems to be decoupled in mammals.
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Affiliation(s)
- Carmen Díez
- SERIDA, Area de Genética y Reproducción Animal, Gijón, Spain.
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38
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Helle S, Helama S, Lertola K. Evolutionary ecology of human birth sex ratio under the compound influence of climate change, famine, economic crises and wars. J Anim Ecol 2009; 78:1226-33. [PMID: 19719518 DOI: 10.1111/j.1365-2656.2009.01598.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. Human sex ratio at birth at the population level has been suggested to vary according to exogenous stressors such as wars, ambient temperature, ecological disasters and economic crises, but their relative effects on birth sex ratio have not been investigated. It also remains unclear whether such associations represent environmental forcing or adaptive parental response, as parents may produce the sex that has better survival prospects and fitness in a given environmental challenge. 2. We examined the simultaneous role of wars, famine, ambient temperature, economic development and total mortality rate on the annual variation of offspring birth sex ratio and whether this variation, in turn, was related to sex-specific infant mortality rate in Finland during 1865-2003. 3. Our findings show an increased excess of male births during the World War II and during warm years. Instead, economic development, famine, short-lasting Finnish civil war and total mortality rate were not related to birth sex ratio. Moreover, we found no association between annual birth sex ratio and sex-biased infant mortality rate among the concurrent cohort. 4. Our results propose that some exogenous challenges like ambient temperature and war can skew human birth sex ratio and that these deviations likely represent environmental forcing rather than adaptive parental response to such challenges.
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Affiliation(s)
- Samuli Helle
- Section of Ecology, Department of Biology, University of Turku, Turku, Finland
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39
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James WH. The variances of the distributions of the combinations of the sexes within mammalian litters: notes to mark the centenary of the problem. J Theor Biol 2009; 259:264-8. [PMID: 19336236 DOI: 10.1016/j.jtbi.2009.03.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Revised: 02/19/2009] [Accepted: 03/13/2009] [Indexed: 11/16/2022]
Abstract
It is 100 years since Gini noted that in some samples of litters of mice and rabbits, the variances of the distributions of the combinations of the sexes are sub-binomial. In other words, in contrast with binomial expectation, there are too many litters in which the sexes are equally balanced, and there are too few unisexual litters. In the intervening years, this finding has been replicated in a number of further species, but no explanation has become established. Potential explanations are reviewed here, and it is suggested that the most likely cause is that, at the time of formation of the zygotes, p, the probability that a zygote will be male, varies from one zygote to another within litters, thus constituting an example of Poisson variation. And it is a standard result in probability theory that such variation causes sub-binomial variance.
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Affiliation(s)
- William H James
- The Galton Laboratory, Department of Genetics, Evolution and Environment, University College London, Wolfson House, 4 Stephenson Way, London NW 1 2 HE, UK.
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40
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Grant VJ, Irwin RJ. A simple model for adaptive variation in the sex ratios of mammalian offspring. J Theor Biol 2009; 258:38-42. [PMID: 19490877 DOI: 10.1016/j.jtbi.2009.01.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Revised: 01/09/2009] [Accepted: 01/09/2009] [Indexed: 11/26/2022]
Abstract
We present a simple mathematical model that describes how primary and secondary sex ratios of offspring may vary adaptively in order to maintain equal numbers of the sexes at the age of reproductive maturity. The model postulates that the sex of an offspring depends probabilistically on a weighted linear combination of maternal testosterone and male vulnerability. The model operates at population level, and is based on three physiological phenomena: first that maternal testosterone in follicular fluid is normally distributed, with levels above the mean more likely to be associated with the conception of males; secondly, that males are more vulnerable than females from conception onwards; and thirdly that under conditions of chronic stress, increased secretion of female testosterone coincides with increased male vulnerability. Thus during times of chronic stress, more males are conceived, but their number of live births is moderated by increased male loss. Variations in secondary sex ratios should therefore be related not only to the stressfulness of environmental conditions, but also to the timing of changes in stressfulness.
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Affiliation(s)
- Valerie J Grant
- Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1. New Zealand.
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Helle S, Lilley T. Maternal 2nd to 4th digit ratio does not predict lifetime offspring sex ratio at birth. Am J Hum Biol 2008; 20:700-3. [PMID: 18561146 DOI: 10.1002/ajhb.20796] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Samuli Helle
- Department of Biology, Section of Ecology, University of Turku, FI-20014 Turku, Finland.
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Grant V, Irwin R, Standley N, Shelling A, Chamley L. Sex of Bovine Embryos May Be Related to Mothers' Preovulatory Follicular Testosterone1. Biol Reprod 2008; 78:812-5. [DOI: 10.1095/biolreprod.107.066050] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Helle S, Helama S, Jokela J. Temperature-related birth sex ratio bias in historical Sami: warm years bring more sons. Biol Lett 2008; 4:60-2. [PMID: 18042510 DOI: 10.1098/rsbl.2007.0482] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The birth sex ratio of vertebrates with chromosomal sex determination has been shown to respond to environmental variability, such as temperature. However, in humans the few previous studies on environmental temperature and birth sex ratios have produced mixed results. We examined whether reconstructed annual mean temperatures were associated with annual offspring sex ratio at birth in the eighteenth to nineteenth century Sami from northern Finland. We found that warm years correlated with a male-biased sex ratio, whereas a warm previous year skewed sex ratio towards females. The net effect of one degree Celsius increase in mean temperature during these 2 years corresponded to approximately 1% more sons born annually. Although the physiological and ecological mechanisms mediating these effects and their evolutionary consequences on parental fitness remain unknown, our results show that environmental temperature may affect human birth sex ratio.
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Affiliation(s)
- Samuli Helle
- Section of Ecology, Department of Biology, University of Turku, 20014 Turku, Finland.
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Some comments on the paper of Grant (2007). J Theor Biol 2008; 253:401-4. [PMID: 18455193 DOI: 10.1016/j.jtbi.2008.03.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 11/29/2007] [Accepted: 03/10/2008] [Indexed: 11/24/2022]
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Helle S, Laaksonen T, Adamsson A, Paranko J, Huitu O. Female field voles with high testosterone and glucose levels produce male-biased litters. Anim Behav 2008. [DOI: 10.1016/j.anbehav.2007.08.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Abstract
Evolutionary biologists and psychologists have long been aware of maternal effects on the secondary sex ratio in mammals. Up till now these have appeared inconsistent but re-analysis of the evidence, focusing on normally distributed maternal testosterone and its physiological and behavioral sequelae, reveals some support for the existence of sex-of-offspring differences between mothers. In addition to the animal studies showing a relationship between maternal, testosterone-based dominance and the secondary sex ratio, research on human mothers shows sex-of-offspring differences in a range of testosterone—related attributes (physiological, behavioral and cognitive) measured at varying times from before the child was conceived to the mother's maturity. Further exploration of these differences might help elucidate the problems surrounding sex determination in mammals.
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Affiliation(s)
- Valerie J. Grant
- Department of Psychological Medicine, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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Grant VJ. Could maternal testosterone levels govern mammalian sex ratio deviations? J Theor Biol 2007; 246:708-19. [PMID: 17379251 DOI: 10.1016/j.jtbi.2007.02.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Revised: 02/06/2007] [Accepted: 02/08/2007] [Indexed: 10/23/2022]
Abstract
Although maternal dominance and good condition are frequently associated with raised offspring sex ratios in mammals, the key factor may be female testosterone, which not only underpins the behavioural indicators but could also provide a pathway to a possible proximate mechanism for sex determination. By taking into account the fact that female testosterone levels rise in response to environmental stressors, it is possible to re-interpret the findings of atypical sex ratios in mammals in a way that reconciles seemingly conflicting results and reveals instead what could be a coherent, adaptive system of sex allocation in mammals.
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Affiliation(s)
- Valerie J Grant
- Psychological Medicine, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland 1, New Zealand.
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Abstract
Although contemporary methods of physically separating X from Y chromosome-bearing spermatozoa are now very efficient, overall fertility rates following the use of sex-sorted sperm are not as impressive, in spite of many attempts to improve them. At the same time, there are suggestions from evolutionary biology, and from sex allocation theory in particular, that there may need to be a modification to the chance theory of sex determination in mammals. This is because it now appears that the mammalian female could have some influence on the sex of her offspring, and furthermore, that this influence could be preconceptual. If so, this could go some way towards accounting for the putative inefficiencies in fertilization following insemination with sex-sorted sperm.
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Affiliation(s)
- Valerie J Grant
- Department of Psychological Medicine, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
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Abstract
At present there appear to be two main categories of problems involved in the ethics of sex selection. The first has to do with the status of the embryo, and the second has to do with the social consequences of making sex selection widely available. However, these may not be the only issues. There is growing evidence from evolutionary psychology and biology, which suggests that the sex of the offspring in mammals may not, after all, be a matter of chance. Instead, sex allocation in mammals may be the result of a finely tuned adaptive process involving the current suitability of a mother to conceive an offspring of a particular sex. If so, we need to know more about this process before embarking on a social policy that could have disadvantageous outcomes for children, their parents and society as a whole.
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Affiliation(s)
- V J Grant
- Department of Psychological Medicine, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.
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