1
|
Foster JA, Walsh SK, Havens K, Kramer AT, Fant JB. Supporting long-term sustainability of ex situ collections using a pedigree-based population management approach. APPLICATIONS IN PLANT SCIENCES 2022; 10:e11491. [PMID: 36258785 PMCID: PMC9575128 DOI: 10.1002/aps3.11491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 03/21/2022] [Accepted: 03/27/2022] [Indexed: 06/16/2023]
Abstract
Premise Living collections maintained for generations are at risk of diversity loss, inbreeding, and adaptation to cultivation. To address these concerns, the zoo community uses pedigrees to track individuals and implement crosses that maximize founder contributions and minimize inbreeding. Using a pedigree management approach, we demonstrate how conducting strategic crosses can minimize genetic issues that have arisen under current practices. Methods We performed crosses between collections and compared progeny fitness, including plant performance and reproductive health. We genotyped the progeny and parental accessions to measure changes in diversity and relatedness within and between accessions. Results The mean relatedness values among individuals within each accession suggest they are full siblings, demonstrating that there was high inbreeding and low diversity within accessions, although less so among accessions. Progeny from the wider crosses had increased genetic diversity and were larger and more fertile, while self-pollinated accessions were smaller and less fertile. Discussion Institutions that hold exceptional species should consider how diversity is maintained within their collections. Implementing a pedigree-based approach to managing plant reproduction ex situ will slow the inevitable loss of genetic diversity and, in turn, result in healthier collections.
Collapse
Affiliation(s)
- Jeremy A. Foster
- Program in Plant Biology and ConservationNorthwestern University2205 Tech DriveEvanstonIllinois60208USA
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden1000 Lake Cook RoadGlencoeIllinois60022USA
| | - Seana K. Walsh
- Department of Science and ConservationNational Tropical Botanical Garden3530 Papalina RoadKalāheoHawaiʻi96741USA
- Natural History Museum of DenmarkUniversity of CopenhagenDK‐2100CopenhagenDenmark
| | - Kayri Havens
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden1000 Lake Cook RoadGlencoeIllinois60022USA
| | - Andrea T. Kramer
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden1000 Lake Cook RoadGlencoeIllinois60022USA
| | - Jeremie B. Fant
- Negaunee Institute for Plant Conservation Science and Action, Chicago Botanic Garden1000 Lake Cook RoadGlencoeIllinois60022USA
| |
Collapse
|
2
|
Stetsenko R, Roze D. The evolution of recombination in self-fertilizing organisms. Genetics 2022; 222:6656355. [PMID: 35929790 PMCID: PMC9434187 DOI: 10.1093/genetics/iyac114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cytological data from flowering plants suggest that the evolution of recombination rates is affected by the mating system of organisms, as higher chiasma frequencies are often observed in self-fertilizing species compared with their outcrossing relatives. Understanding the evolutionary cause of this effect is of particular interest, as it may shed light on the selective forces favoring recombination in natural populations. While previous models showed that inbreeding may have important effects on selection for recombination, existing analytical treatments are restricted to the case of loosely linked loci and weak selfing rates, and ignore the stochastic effect of genetic interference (Hill-Robertson effect), known to be an important component of selection for recombination in randomly mating populations. In this article, we derive general expressions quantifying the stochastic and deterministic components of selection acting on a mutation affecting the genetic map length of a whole chromosome along which deleterious mutations occur, valid for arbitrary selfing rates. The results show that selfing generally increases selection for recombination caused by interference among mutations as long as selection against deleterious alleles is sufficiently weak. While interference is often the main driver of selection for recombination under tight linkage or high selfing rates, deterministic effects can play a stronger role under intermediate selfing rates and high recombination, selecting against recombination in the absence of epistasis, but favoring recombination when epistasis is negative. Individual-based simulation results indicate that our analytical model often provides accurate predictions for the strength of selection on recombination under partial selfing.
Collapse
Affiliation(s)
- Roman Stetsenko
- CNRS, IRL 3614 Evolutionary Biology and Ecology of Algae, 29688 Roscoff, France.,Sorbonne Université, Station Biologique de Roscoff, 29688 Roscoff, France
| | - Denis Roze
- CNRS, IRL 3614 Evolutionary Biology and Ecology of Algae, 29688 Roscoff, France.,Sorbonne Université, Station Biologique de Roscoff, 29688 Roscoff, France
| |
Collapse
|
3
|
Wang P, Hou R, Wu Y, Zhang Z, Que P, Chen P. Genomic status of yellow-breasted bunting following recent rapid population decline. iScience 2022; 25:104501. [PMID: 35733787 PMCID: PMC9207672 DOI: 10.1016/j.isci.2022.104501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/04/2022] [Accepted: 05/26/2022] [Indexed: 12/03/2022] Open
Abstract
Global biodiversity is facing serious threats. However, knowledge of the genomic consequences of recent rapid population declines of wild organisms is limited. Do populations experiencing recent rapid population decline have the same genomic status as wild populations that experience long-term declines? Yellow-breasted Bunting (Emberiza aureola) is a critically endangered species that has been experiencing a recent rapid population decline. To answer the question, we assembled and annotated the whole genome of Yellow-breasted Bunting. Furthermore, we found high genetic diversity, low linkage disequilibrium, and low proportion of long runs of homozygosity in Yellow-breasted Bunting, suggesting that the populations following recent rapid declines have different genomic statuses from the population that experienced long-term population decline.
Collapse
Affiliation(s)
- Pengcheng Wang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Rong Hou
- Chengdu Research Base of Giant Panda Breeding, Sichuan Key Laboratory of Conservation Biology for Endangered Wildlife, Chengdu, 610081, P. R. China
| | - Yang Wu
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing 100875, P. R. China
| | - Zhengwang Zhang
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing 100875, P. R. China
| | - Pinjia Que
- Chengdu Research Base of Giant Panda Breeding, Sichuan Key Laboratory of Conservation Biology for Endangered Wildlife, Chengdu, 610081, P. R. China
- Sichuan Academy of Giant Panda, Chengdu 610086, P. R. China
| | - Peng Chen
- Chengdu Research Base of Giant Panda Breeding, Sichuan Key Laboratory of Conservation Biology for Endangered Wildlife, Chengdu, 610081, P. R. China
- Sichuan Academy of Giant Panda, Chengdu 610086, P. R. China
| |
Collapse
|
4
|
DeWoody JA, Harder AM, Mathur S, Willoughby JR. The long-standing significance of genetic diversity in conservation. Mol Ecol 2021; 30:4147-4154. [PMID: 34191374 DOI: 10.1111/mec.16051] [Citation(s) in RCA: 73] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 06/20/2021] [Accepted: 06/28/2021] [Indexed: 12/12/2022]
Abstract
Since allozymes were first used to assess genetic diversity in the 1960s and 1970s, biologists have attempted to characterize gene pools and conserve the diversity observed in domestic crops, livestock, zoos and (more recently) natural populations. Recently, some authors have claimed that the importance of genetic diversity in conservation biology has been greatly overstated. Here, we argue that a voluminous literature indicates otherwise. We address four main points made by detractors of genetic diversity's role in conservation by using published literature to firmly establish that genetic diversity is intimately tied to evolutionary fitness, and that the associated demographic consequences are of paramount importance to many conservation efforts. We think that responsible management in the Anthropocene should, whenever possible, include the conservation of ecosystems, communities, populations and individuals, and their underlying genetic diversity.
Collapse
Affiliation(s)
- J Andrew DeWoody
- Department of Forestry and Natural Resources, Department of Biological Sciences, Purdue University, West Lafayette, Indiana, USA
| | - Avril M Harder
- School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama, USA
| | - Samarth Mathur
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, Ohio, USA
| | - Janna R Willoughby
- School of Forestry and Wildlife Sciences, Auburn University, Auburn, Alabama, USA
| |
Collapse
|
5
|
Abu Awad D, Roze D. Epistasis, inbreeding depression, and the evolution of self-fertilization. Evolution 2020; 74:1301-1320. [PMID: 32386235 DOI: 10.1111/evo.13961] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 02/21/2020] [Indexed: 11/29/2022]
Abstract
Inbreeding depression resulting from partially recessive deleterious alleles is thought to be the main genetic factor preventing self-fertilizing mutants from spreading in outcrossing hermaphroditic populations. However, deleterious alleles may also generate an advantage to selfers in terms of more efficient purging, while the effects of epistasis among those alleles on inbreeding depression and mating system evolution remain little explored. In this article, we use a general model of selection to disentangle the effects of different forms of epistasis (additive-by-additive, additive-by-dominance, and dominance-by-dominance) on inbreeding depression and on the strength of selection for selfing. Models with fixed epistasis across loci, and models of stabilizing selection acting on quantitative traits (generating distributions of epistasis) are considered as special cases. Besides its effects on inbreeding depression, epistasis may increase the purging advantage associated with selfing (when it is negative on average), while the variance in epistasis favors selfing through the generation of linkage disequilibria that increase mean fitness. Approximations for the strengths of these effects are derived, and compared with individual-based simulation results.
Collapse
Affiliation(s)
- Diala Abu Awad
- Department of Population Genetics, Technical University of Munich, Munich, 80333, Germany
| | - Denis Roze
- Evolutionary Biology and Ecology of Algae, UMI 3614, CNRS, Roscoff, 29688, France.,Station Biologique de Roscoff, Sorbonne Université, Roscoff, 29688, France
| |
Collapse
|
6
|
Brown KE, Kelly JK. Severe inbreeding depression is predicted by the “rare allele load” in
Mimulus guttatus
*. Evolution 2019; 74:587-596. [DOI: 10.1111/evo.13876] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 09/30/2019] [Accepted: 10/09/2019] [Indexed: 01/04/2023]
Affiliation(s)
- Keely E. Brown
- Ecology and Evolutionary Biology University of Kansas Lawrence Kansas 66045
| | - John K. Kelly
- Ecology and Evolutionary Biology University of Kansas Lawrence Kansas 66045
| |
Collapse
|
7
|
Colicchio J, Monnahan PJ, Wessinger CA, Brown K, Kern JR, Kelly JK. Individualized mating system estimation using genomic data. Mol Ecol Resour 2019; 20:333-347. [DOI: 10.1111/1755-0998.13094] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 07/27/2019] [Accepted: 08/19/2019] [Indexed: 11/29/2022]
Affiliation(s)
- Jack Colicchio
- Department of Ecology and Evolutionary Biology University of Kansas Lawrence KS USA
| | - Patrick J. Monnahan
- Department of Ecology and Evolutionary Biology University of Kansas Lawrence KS USA
| | - Carolyn A. Wessinger
- Department of Ecology and Evolutionary Biology University of Kansas Lawrence KS USA
| | - Keely Brown
- Department of Ecology and Evolutionary Biology University of Kansas Lawrence KS USA
| | - James Russell Kern
- Department of Ecology and Evolutionary Biology University of Kansas Lawrence KS USA
| | - John K. Kelly
- Department of Ecology and Evolutionary Biology University of Kansas Lawrence KS USA
| |
Collapse
|
8
|
Domínguez-García S, García C, Quesada H, Caballero A. Accelerated inbreeding depression suggests synergistic epistasis for deleterious mutations in Drosophila melanogaster. Heredity (Edinb) 2019; 123:709-722. [PMID: 31477803 PMCID: PMC6834575 DOI: 10.1038/s41437-019-0263-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 08/15/2019] [Accepted: 08/18/2019] [Indexed: 01/21/2023] Open
Abstract
Epistasis may have important consequences for a number of issues in quantitative genetics and evolutionary biology. In particular, synergistic epistasis for deleterious alleles is relevant to the mutation load paradox and the evolution of sex and recombination. Some studies have shown evidence of synergistic epistasis for spontaneous or induced deleterious mutations appearing in mutation-accumulation experiments. However, many newly arising mutations may not actually be segregating in natural populations because of the erasing action of natural selection. A demonstration of synergistic epistasis for naturally segregating alleles can be achieved by means of inbreeding depression studies, as deleterious recessive allelic effects are exposed in inbred lines. Nevertheless, evidence of epistasis from these studies is scarce and controversial. In this paper, we report the results of two independent inbreeding experiments carried out with two different populations of Drosophila melanogaster. The results show a consistent accelerated inbreeding depression for fitness, suggesting synergistic epistasis among deleterious alleles. We also performed computer simulations assuming different possible models of epistasis and mutational parameters for fitness, finding some of them to be compatible with the results observed. Our results suggest that synergistic epistasis for deleterious mutations not only occurs among newly arisen spontaneous or induced mutations, but also among segregating alleles in natural populations.
Collapse
Affiliation(s)
- Sara Domínguez-García
- Departamento de Bioquímica, Genética e Inmunología, Universidade de Vigo, 36310, Vigo, Spain.,Centro de Investigación Marina (CIM-UVIGO), Universidade de Vigo, 36310, Vigo, Spain
| | - Carlos García
- CIBUS, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Galicia, Spain
| | - Humberto Quesada
- Departamento de Bioquímica, Genética e Inmunología, Universidade de Vigo, 36310, Vigo, Spain.,Centro de Investigación Marina (CIM-UVIGO), Universidade de Vigo, 36310, Vigo, Spain
| | - Armando Caballero
- Departamento de Bioquímica, Genética e Inmunología, Universidade de Vigo, 36310, Vigo, Spain. .,Centro de Investigación Marina (CIM-UVIGO), Universidade de Vigo, 36310, Vigo, Spain.
| |
Collapse
|
9
|
Toll K, Willis JH. Hybrid inviability and differential submergence tolerance drive habitat segregation between two congeneric monkeyflowers. Ecology 2018; 99:2776-2786. [DOI: 10.1002/ecy.2529] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 09/10/2018] [Accepted: 09/18/2018] [Indexed: 12/25/2022]
Affiliation(s)
- Katherine Toll
- Department of Biology Duke University Durham North Carolina 27708 USA
- Department of Plant Biology Michigan State University East Lansing Michigan 48824 USA
| | - John H. Willis
- Department of Biology Duke University Durham North Carolina 27708 USA
| |
Collapse
|
10
|
Ferris KG, Willis JH. Differential adaptation to a harsh granite outcrop habitat between sympatric
Mimulus
species. Evolution 2018; 72:1225-1241. [DOI: 10.1111/evo.13476] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 02/20/2018] [Accepted: 02/28/2018] [Indexed: 12/11/2022]
Affiliation(s)
- Kathleen G. Ferris
- Department of Biology Duke University 125 Science Drive Durham North Carolina 27705
- Current Address: Center for Population Biology, 2320 Storer Hall University of California Davis One Shields Avenue Davis California 95616
| | - John H. Willis
- Department of Biology Duke University 125 Science Drive Durham North Carolina 27705
| |
Collapse
|
11
|
Obolski U, Ram Y, Hadany L. Key issues review: evolution on rugged adaptive landscapes. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:012602. [PMID: 29051394 DOI: 10.1088/1361-6633/aa94d4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Adaptive landscapes represent a mapping between genotype and fitness. Rugged adaptive landscapes contain two or more adaptive peaks: allele combinations with higher fitness than any of their neighbors in the genetic space. How do populations evolve on such rugged landscapes? Evolutionary biologists have struggled with this question since it was first introduced in the 1930s by Sewall Wright. Discoveries in the fields of genetics and biochemistry inspired various mathematical models of adaptive landscapes. The development of landscape models led to numerous theoretical studies analyzing evolution on rugged landscapes under different biological conditions. The large body of theoretical work suggests that adaptive landscapes are major determinants of the progress and outcome of evolutionary processes. Recent technological advances in molecular biology and microbiology allow experimenters to measure adaptive values of large sets of allele combinations and construct empirical adaptive landscapes for the first time. Such empirical landscapes have already been generated in bacteria, yeast, viruses, and fungi, and are contributing to new insights about evolution on adaptive landscapes. In this Key Issues Review we will: (i) introduce the concept of adaptive landscapes; (ii) review the major theoretical studies of evolution on rugged landscapes; (iii) review some of the recently obtained empirical adaptive landscapes; (iv) discuss recent mathematical and statistical analyses motivated by empirical adaptive landscapes, as well as provide the reader with instructions and source code to implement simulations of evolution on adaptive landscapes; and (v) discuss possible future directions for this exciting field.
Collapse
|
12
|
Case AL, Finseth FR, Barr CM, Fishman L. Selfish evolution of cytonuclear hybrid incompatibility in Mimulus. Proc Biol Sci 2017; 283:rspb.2016.1493. [PMID: 27629037 DOI: 10.1098/rspb.2016.1493] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 08/23/2016] [Indexed: 11/12/2022] Open
Abstract
Intraspecific coevolution between selfish elements and suppressors may promote interspecific hybrid incompatibility, but evidence of this process is rare. Here, we use genomic data to test alternative models for the evolution of cytonuclear hybrid male sterility in Mimulus In hybrids between Iron Mountain (IM) Mimulus guttatus × Mimulus nasutus, two tightly linked M. guttatus alleles (Rf1/Rf2) each restore male fertility by suppressing a local mitochondrial male-sterility gene (IM-CMS). Unlike neutral models for the evolution of hybrid incompatibility loci, selfish evolution predicts that the Rf alleles experienced strong selection in the presence of IM-CMS. Using whole-genome sequences, we compared patterns of population-genetic variation in Rf at IM to a neighbouring population that lacks IM-CMS. Consistent with local selection in the presence of IM-CMS, the Rf region shows elevated FST, high local linkage disequilibrium and a distinct haplotype structure at IM, but not at Cone Peak (CP), suggesting a recent sweep in the presence of IM-CMS. In both populations, Rf2 exhibited lower polymorphism than other regions, but the low-diversity outliers were different between CP and IM. Our results confirm theoretical predictions of ubiquitous cytonuclear conflict in plants and provide a population-genetic mechanism for the evolution of a common form of hybrid incompatibility.
Collapse
Affiliation(s)
- Andrea L Case
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Findley R Finseth
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Camille M Barr
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Lila Fishman
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| |
Collapse
|
13
|
Pray LA, Goodnight CJ. GENETIC VARIATION IN INBREEDING DEPRESSION IN THE RED FLOUR BEETLE TRIBOLIUM CASTANEUM. Evolution 2017; 49:176-188. [PMID: 28593675 DOI: 10.1111/j.1558-5646.1995.tb05969.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/1993] [Accepted: 04/22/1994] [Indexed: 11/27/2022]
Abstract
Inbreeding depression varies among species and among populations within a species. Few studies, however, have considered the extent to which inbreeding depression varies within a single population. We report on two experiments to provide evidence that inbreeding depression is genetically variable, such that within a single population some lineages suffer severe inbreeding depression, others suffer only mild inbreeding depression, and some lineages actually increase in phenotypic value at higher levels of inbreeding. We examine the effects of population structure on inbreeding depression for two traits in the first experiment (adult dry weight and female relative fitness), and for seven traits in the second experiment (female and male adult dry weight, female and male relative fitness, female and male developmental time, and egg-to-adult viability). In the first experiment, we collected data from 4 families within each of 38 lineages derived from a single ancestral stock population and maintained for four generations of full-sib mating. Both traits demonstrate significant inbreeding depression and provide evidence that even within a single lineage there is significant genetic variability in inbreeding depression. In the second experiment, we collected data from 5 replicates for each of 15 lineages derived from the same ancestral population used in the first experiment; these lineages were maintained for four generations of full-sib mating. We also collected data on outbred control beetles in each generation and incorporated these data into the analyses to account for environmental effects in an unbiased manner. All traits except female and male developmental time show significant inbreeding depression. All traits showing inbreeding depression are genetically variable in inbreeding depression, as is evident from a significant linear lineage-×-f component. For both experiments, the effect of population structure on inbreeding depression is further evident from the increasing amount of variation that can be explained by the models used to measure inbreeding depression when additional levels of population structure are included. Genetic variation in inbreeding depression has important implications for conservation biology and may be an important factor in mating-system evolution.
Collapse
Affiliation(s)
- Leslie A Pray
- Department of Biology, University of Vermont, Marsh Life Science Building, Burlington, Vermont, 05405-0086
| | - Charles J Goodnight
- Department of Biology, University of Vermont, Marsh Life Science Building, Burlington, Vermont, 05405-0086
| |
Collapse
|
14
|
Chang S, Rausher MD. THE ROLE OF INBREEDING DEPRESSION IN MAINTAINING THE MIXED MATING SYSTEM OF THE COMMON MORNING GLORY,
IPOMOEA PURPUREA. Evolution 2017; 53:1366-1376. [DOI: 10.1111/j.1558-5646.1999.tb05401.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/1998] [Accepted: 04/20/1999] [Indexed: 10/19/2022]
Affiliation(s)
- Shu‐Mei Chang
- Department of Zoology Duke University Box 90325 Durham North Carolina 27708‐0325
| | - Mark D. Rausher
- Department of Zoology Duke University Box 90325 Durham North Carolina 27708‐0325
| |
Collapse
|
15
|
Mayer SS, Charlesworth D, Meyers B. INBREEDING DEPRESSION IN FOUR POPULATIONS OF COLLINSIA HETEROPHYLLA
NUTT (SCROPHULARIACEAE). Evolution 2017; 50:879-891. [DOI: 10.1111/j.1558-5646.1996.tb03896.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/1994] [Accepted: 04/05/1995] [Indexed: 12/01/2022]
Affiliation(s)
- Stephanie S. Mayer
- Department of Ecology and Evolution; The University of Chicago; 1101 East 57th Street Chicago Illinois 60637-1573
| | - Deborah Charlesworth
- Department of Ecology and Evolution; The University of Chicago; 1101 East 57th Street Chicago Illinois 60637-1573
| | - Blake Meyers
- Department of Vegetable Crops; University of California; Davis California 95616
| |
Collapse
|
16
|
Newman D, Pilson D. INCREASED PROBABILITY OF EXTINCTION DUE TO DECREASED GENETIC EFFECTIVE POPULATION SIZE: EXPERIMENTAL POPULATIONS OF CLARKIA PULCHELLA. Evolution 2017; 51:354-362. [PMID: 28565367 DOI: 10.1111/j.1558-5646.1997.tb02422.x] [Citation(s) in RCA: 228] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/1995] [Accepted: 10/07/1996] [Indexed: 11/29/2022]
Abstract
We established replicated experimental populations of the annual plant Clarkia pulchella to evaluate the existence of a causal relationship between loss of genetic variation and population survival probability. Two treatments differing in the relatedness of the founders, and thus in the genetic effective population size (Ne ), were maintained as isolated populations in a natural environment. After three generations, the low Ne treatment had significantly lower germination and survival rates than did the high Ne treatment. These lower germination and survival rates led to decreased mean fitness in the low Ne populations: estimated mean fitness in the low Ne populations was only 21% of the estimated mean fitness in the high Ne populations. This inbreeding depression led to a reduction in population survival: at the conclusion of the experiment, 75% of the high Ne populations were still extant, whereas only 31% of the low Ne populations had survived. Decreased genetic effective population size, which leads to both inbreeding and the loss of alleles by genetic drift, increased the probability of population extinction over that expected from demographic and environmental stochasticity alone. This demonstrates that the genetic effective population size can strongly affect the probability of population persistence.
Collapse
Affiliation(s)
- Dara Newman
- Division of Biological Sciences, University of Montana, Missoula, Montana, 59812
| | - Diana Pilson
- School of Biological Sciences, 348 Manter Hall, University of Nebraska, Lincoln, Nebraska, 68588-0118
| |
Collapse
|
17
|
Willis JH. THE ROLE OF GENES OF LARGE EFFECT ON INBREEDING DEPRESSION IN MIMULUS GUTTATUS. Evolution 2017; 53:1678-1691. [PMID: 28565461 DOI: 10.1111/j.1558-5646.1999.tb04553.x] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/1998] [Accepted: 06/10/1999] [Indexed: 11/28/2022]
Abstract
Severe inbreeding depression is routinely observed in outcrossing species. If inbreeding load is due largely to deleterious alleles of large effect, such as recessive lethals or steriles, then most of it is expected to be purged during brief periods of inbreeding. In contrast, if inbreeding depression is due to the cumulative effects of many deleterious alleles of small effect, then it will be maintained in the face of periodic inbreeding. Whether or not inbreeding depression can be purged with inbreeding in the short term has important implications for the evolution of mating systems and the probability that a small population will go extinct. In this paper I evaluate the extent to which the tremendous inbreeding load in a primarily outcrossing population of the wildflower, Mimulus guttatus, is due to alleles of large effect. To do this, I first constructed a large outbred "ancestral" population by randomly mating plants collected as seeds from a natural population. From this population I formed 1200 lines that were maintained by self-fertilization and single seedling descent: after five generations of selling, 335 lines had survived the inbreeding process. Selection during the line formation is expected to have largely purged alleles of large effect from the collection of highly inbred lines. Because alleles with minor effects on fitness should have been effectively neutral, the inbreeding depression due to this class of genes should have been unchanged. The inbred lines were intercrossed to form a large, outcrossed "purged" population. Finally, I estimated the fitness of outbred and selfed progeny from the ancestral and purged populations to determine the contribution of major deleterious alleles on inbreeding depression. I found that although the average fitness of the outcrossed progeny nearly doubled following purging, the limited decline in inbreeding depression and limited increase in inbred fitness indicates that alleles of large effect are not the principle cause of inbreeding depression in this population. In aggregate, the data suggest that lethals and steriles make a minority contribution to inbreeding depression and that the increased outbred fitness is due primarily to adaptation to greenhouse conditions.
Collapse
Affiliation(s)
- John H Willis
- Department of Biology, University of Oregon, Eugene, Oregon, 97403
| |
Collapse
|
18
|
del Castillo RF. FITNESS CONSEQUENCES OF MATERNAL AND NONMATERNAL COMPONENTS OF INBREEDING IN THE GYNODIOECIOUSPHACELIA DUBIA. Evolution 2017; 52:44-60. [DOI: 10.1111/j.1558-5646.1998.tb05137.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/1997] [Accepted: 10/02/1997] [Indexed: 11/29/2022]
|
19
|
Montalvo AM, Shaw RG. QUANTITATIVE GENETICS OF SEQUENTIAL LIFE‐HISTORY AND JUVENILE TRAITS IN THE PARTIALLY SELFING PERENNIAL,
AQUILEGIA CAERULEA. Evolution 2017; 48:828-841. [DOI: 10.1111/j.1558-5646.1994.tb01365.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/1992] [Accepted: 09/07/1993] [Indexed: 12/01/2022]
Affiliation(s)
- Arlee M. Montalvo
- Department of Biology University of California Riverside California 92521
| | - Ruth G. Shaw
- Department of Botany and Plant Sciences University of California Riverside California 92521
| |
Collapse
|
20
|
Willis JH. MEASURES OF PHENOTYPIC SELECTION ARE BIASED BY PARTIAL INBREEDING. Evolution 2017; 50:1501-1511. [DOI: 10.1111/j.1558-5646.1996.tb03923.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/1995] [Accepted: 08/24/1995] [Indexed: 11/30/2022]
Affiliation(s)
- John H. Willis
- Department of Biology University of Oregon Eugene Oregon 97403
| |
Collapse
|
21
|
Carr DE, Dudash MR. THE EFFECTS OF FIVE GENERATIONS OF ENFORCED SELFING ON POTENTIAL MALE AND FEMALE FUNCTION IN
MIMULUS GUTTATUS. Evolution 2017; 51:1797-1807. [DOI: 10.1111/j.1558-5646.1997.tb05103.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/1996] [Accepted: 08/11/1997] [Indexed: 11/28/2022]
Affiliation(s)
- David E. Carr
- Departments of Plant Biology and Zoology University of Maryland College Park Maryland 20742
| | - Michele R. Dudash
- Departments of Plant Biology and Zoology University of Maryland College Park Maryland 20742
- Maryland Agricultural Experiment Station University of Maryland College Park Maryland 20742
| |
Collapse
|
22
|
Dudash MR, Carr DE, Fenster CB. FIVE GENERATIONS OF ENFORCED SELFING AND OUTCROSSING IN
MIMULUS GUTTATUS
: INBREEDING DEPRESSION VARIATION AT THE POPULATION AND FAMILY LEVEL. Evolution 2017; 51:54-65. [DOI: 10.1111/j.1558-5646.1997.tb02388.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/1995] [Accepted: 08/02/1996] [Indexed: 11/29/2022]
Affiliation(s)
- Michele R. Dudash
- Department of Plant Biology University of Maryland College Park Maryland 20742‐5815
- Maryland Agricultural Experiment Station University of Maryland College Park Maryland 20742‐5815
| | - David E. Carr
- Department of Plant Biology University of Maryland College Park Maryland 20742‐5815
| | - Charles B. Fenster
- Department of Plant Biology University of Maryland College Park Maryland 20742‐5815
| |
Collapse
|
23
|
Ferris KG, Barnett LL, Blackman BK, Willis JH. The genetic architecture of local adaptation and reproductive isolation in sympatry within the Mimulus guttatus species complex. Mol Ecol 2016; 26:208-224. [PMID: 27439150 DOI: 10.1111/mec.13763] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 06/30/2016] [Accepted: 07/05/2016] [Indexed: 01/05/2023]
Abstract
The genetic architecture of local adaptation has been of central interest to evolutionary biologists since the modern synthesis. In addition to classic theory on the effect size of adaptive mutations by Fisher, Kimura and Orr, recent theory addresses the genetic architecture of local adaptation in the face of ongoing gene flow. This theory predicts that with substantial gene flow between populations local adaptation should proceed primarily through mutations of large effect or tightly linked clusters of smaller effect loci. In this study, we investigate the genetic architecture of divergence in flowering time, mating system-related traits, and leaf shape between Mimulus laciniatus and a sympatric population of its close relative M. guttatus. These three traits are probably involved in M. laciniatus' adaptation to a dry, exposed granite outcrop environment. Flowering time and mating system differences are also reproductive isolating barriers making them 'magic traits'. Phenotypic hybrids in this population provide evidence of recent gene flow. Using next-generation sequencing, we generate dense SNP markers across the genome and map quantitative trait loci (QTLs) involved in flowering time, flower size and leaf shape. We find that interspecific divergence in all three traits is due to few QTL of large effect including a highly pleiotropic QTL on chromosome 8. This QTL region contains the pleiotropic candidate gene TCP4 and is involved in ecologically important phenotypes in other Mimulus species. Our results are consistent with theory, indicating that local adaptation and reproductive isolation with gene flow should be due to few loci with large and pleiotropic effects.
Collapse
Affiliation(s)
- Kathleen G Ferris
- Department of Biology, Duke University, 125 Science Drive, Durham, NC, 27705, USA
| | - Laryssa L Barnett
- Department of Biology, Duke University, 125 Science Drive, Durham, NC, 27705, USA
| | - Benjamin K Blackman
- Department of Biology, University of Virginia, 485 McCormick Road, Charlottesville, VA, 22904, USA
| | - John H Willis
- Department of Biology, Duke University, 125 Science Drive, Durham, NC, 27705, USA
| |
Collapse
|
24
|
Kenney AM, Sweigart AL. Reproductive isolation and introgression between sympatric
Mimulus
species. Mol Ecol 2016; 25:2499-517. [DOI: 10.1111/mec.13630] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 03/18/2016] [Accepted: 03/22/2016] [Indexed: 01/19/2023]
Affiliation(s)
- Amanda M. Kenney
- Department of Genetics University of Georgia Athens GA 30602 USA
- Department of Biological Sciences St. Edward's University Austin TX 78704 USA
| | | |
Collapse
|
25
|
Sharp NP, Agrawal AF. The decline in fitness with inbreeding: evidence for negative dominance-by-dominance epistasis in Drosophila melanogaster. J Evol Biol 2016; 29:857-64. [PMID: 26709722 DOI: 10.1111/jeb.12815] [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: 10/22/2015] [Revised: 12/17/2015] [Accepted: 12/18/2015] [Indexed: 01/27/2023]
Abstract
Genetic interactions can play an important role in the evolution of reproductive strategies. In particular, negative dominance-by-dominance epistasis for fitness can theoretically favour sex and recombination. This form of epistasis can be detected statistically because it generates nonlinearity in the relationship between fitness and inbreeding coefficient. Measures of fitness in progressively inbred lines tend to show limited evidence for epistasis. However, tests of this kind can be biased against detecting an accelerating decline due to line losses at higher inbreeding levels. We tested for dominance-by-dominance epistasis in Drosophila melanogaster by examining viability at five inbreeding levels that were generated simultaneously, avoiding the bias against detecting nonlinearity that has affected previous studies. We find an accelerating rate of fitness decline with inbreeding, indicating that dominance-by-dominance epistasis is negative on average, which should favour sex and recombination.
Collapse
Affiliation(s)
- N P Sharp
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada.,Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| | - A F Agrawal
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
26
|
Reid JM, Arcese P, Bocedi G, Duthie AB, Wolak ME, Keller LF. Resolving the conundrum of inbreeding depression but no inbreeding avoidance: Estimating sex-specific selection on inbreeding by song sparrows (Melospiza melodia). Evolution 2015; 69:2846-61. [PMID: 26420476 PMCID: PMC5057356 DOI: 10.1111/evo.12780] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 09/04/2015] [Accepted: 09/16/2015] [Indexed: 11/29/2022]
Abstract
Inbreeding avoidance among interacting females and males is not always observed despite inbreeding depression in offspring fitness, creating an apparent "inbreeding paradox." This paradox could be resolved if selection against inbreeding was in fact weak, despite inbreeding depression. However, the net magnitude and direction of selection on the degree to which females and males inbreed by pairing with relatives has not been explicitly estimated. We used long-term pedigree data to estimate phenotypic selection gradients on the degree of inbreeding that female and male song sparrows (Melospiza melodia) expressed by forming socially persistent breeding pairs with relatives. Fitness was measured as the total numbers of offspring and grand offspring contributed to the population, and as corresponding expected numbers of identical-by-descent allele copies, thereby accounting for variation in offspring survival, reproduction, and relatedness associated with variation in parental inbreeding. Estimated selection gradients on the degree to which individuals paired with relatives were weakly positive in females, but negative in males that formed at least one socially persistent pairing. However, males that paired had higher mean fitness than males that remained socially unpaired. These analyses suggest that net selection against inbreeding may be weak in both sexes despite strong inbreeding depression, thereby resolving the "inbreeding paradox."
Collapse
Affiliation(s)
- Jane M Reid
- Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 2TZ, Scotland.
| | - Peter Arcese
- Department of Forest and Conservation Sciences, University of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4
| | - Greta Bocedi
- Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 2TZ, Scotland
| | - A Bradley Duthie
- Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 2TZ, Scotland
| | - Matthew E Wolak
- Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 2TZ, Scotland
| | - Lukas F Keller
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| |
Collapse
|
27
|
Abstract
Recent progress in the genetic analysis of inbreeding depression in plants is reviewed. While the debate over the importance of genes of dominance versus overdominance effect continues, the scope of inferences has widened and now includes such facets as the interactions between genes, the relative abundance of major versus minor genes, life cycle stage expression, and mutation rates. The types of inferences are classified into the genomic, where many genes are characterized as an average, and the genic, where individual genes are characterized. Genomic inferences can be based upon natural levels of inbreeding depression, purging experiments, the comparison of individuals of differing F (e.g., prior inbreeding), and various crossing designs. Genic inferences mainly involve mapping and characterizing loci with genetic markers, involving either a single cross or, ideally, several crosses. Alternative statistical models for analyzing polymorphic loci causing inbreeding depression should be a fruitful problem for geneticists to pursue. Key words : inbreeding depression, genetic load, self-fertilization, QTL mapping.
Collapse
|
28
|
Baker RL, Hileman LC, Diggle PK. Patterns of shoot architecture in locally adapted populations are linked to intraspecific differences in gene regulation. THE NEW PHYTOLOGIST 2012; 196:271-281. [PMID: 22882227 DOI: 10.1111/j.1469-8137.2012.04245.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
• Shoot architecture, including the number and location of branches, is a crucial aspect of plant function, morphological diversification, life history evolution and crop domestication. • Genes controlling shoot architecture are well characterized in, and largely conserved across, model flowering plant species. The role of these genes in the evolution of morphological diversity in natural populations, however, has not been explored. • We identify axillary meristem outgrowth as a primary driver of divergent branch number and life histories in two locally adapted populations of the monkeyflower, Mimulus guttatus. • Furthermore, we show that MORE AXILLARY GROWTH (MAX) gene expression strongly correlates with natural variation in branch outgrowth in this species, linking modification of the MAX-dependent pathway to the evolutionary diversification of shoot architecture.
Collapse
Affiliation(s)
- Robert L Baker
- Department of Ecology and Evolutionary Biology, Campus Box 334, University of Colorado at Boulder, Boulder, CO 80309, USA
- Current address: Department of Botany, University of Wyoming, Laramie WY 80271, USA
| | - Lena C Hileman
- Department of Ecology and Evolutionary Biology, University of Kansas, 1200 Sunnyside Ave, Lawrence, KS 66045, USA
| | - Pamela K Diggle
- Department of Ecology and Evolutionary Biology, Campus Box 334, University of Colorado at Boulder, Boulder, CO 80309, USA
| |
Collapse
|
29
|
Walisch TJ, Colling G, Poncelet M, Matthies D. Effects of inbreeding and interpopulation crosses on performance and plasticity of two generations of offspring of a declining grassland plant. AMERICAN JOURNAL OF BOTANY 2012; 99:1300-1313. [PMID: 22859653 DOI: 10.3732/ajb.1100479] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
PREMISE OF THE STUDY Inbreeding depression is a major evolutionary force and an important topic in conservation genetics because habitat fragmentation leads to increased inbreeding in the populations of many species. Crosses between populations may restore heterozygosity, resulting in increased performance (heterosis), but may also lead to the disruption of coadapted gene complexes and to decreased performance (outbreeding depression). METHODS We investigated the effects of selfing and of within and between population crosses on reproduction and the performance of two generations of offspring of the declining grassland plant Saxifraga granulata (Saxifragaceae). We also subjected the first generation of offspring to a fertilization and two stress treatments (competition and defoliation) to investigate whether the effects of inbreeding and interpopulation gene flow depend on environmental conditions. KEY RESULTS Inbreeding depression affected all traits in the F(1) generation (δ = 0.07-0.55), but was stronger for traits expressed late during development and varied among families. The adaptive plasticity of offspring from selfing and from interpopulation crosses in response to nutrient addition was reduced. Outbreeding depression was also observed in response to stress. Multiplicative fitness of the F(2) generation after serial inbreeding was extremely low (δ > 0.99), but there was heterosis after crossing inbred lines. Outbreeding depression was not observed in the F(2). CONCLUSIONS Continuous inbreeding may drastically reduce the fitness of plants, but effects may be environment-dependent. When assessing the genetic effects of fragmentation and interpopulation crosses, the possible effects on the mean performance of offspring and on its adaptive plasticity should be considered.
Collapse
Affiliation(s)
- Tania J Walisch
- Service biologie des populations, Musée national d'histoire naturelle, Luxembourg, Luxembourg.
| | | | | | | |
Collapse
|
30
|
Baker RL, Diggle PK. Node-specific branching and heterochronic changes underlie population-level differences in Mimulus guttatus (Phrymaceae) shoot architecture. AMERICAN JOURNAL OF BOTANY 2011; 98:1924-1934. [PMID: 22123715 DOI: 10.3732/ajb.1100098] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
PREMISE OF THE STUDY Shoot architecture is a fundamentally developmental aspect of plant biology with implications for plant form, function, reproduction, and life history evolution. Mimulus guttatus is morphologically diverse and becoming a model for evolutionary biology. Shoot architecture, however, has never been studied from a developmental perspective in M. guttatus. METHODS We examined the development of branches and flowers in plants from two locally adapted populations of M. guttatus with contrasting flowering times, life histories, and branch numbers. We planted second-generation seed in growth chambers to control for maternal and environmental effects. KEY RESULTS Most branches occurred at nodes one and two of the main axis. Onset of branching occurred earlier and at a greater frequency in perennials than in annuals. In perennials, almost all flowers occurred at the fifth or more distal nodes. In annuals, most flowers occurred at the third and more distal nodes. Accessory axillary meristems and higher-order branching did not influence shoot architecture. CONCLUSIONS We found no evidence for trade-offs between flowers and branches because axillary meristem number was not limiting: a large number of meristems remained quiescent. If, however, quiescence is a component of meristem allocation strategy, then meristems may be limited despite presence of quiescent meristems. At the two basalmost nodes, branch number was determined by mechanisms governing either meristem initiation or outgrowth, rather than flowering vs. branching. At the third and more distal nodes, heterochronic processes contributed to flowering time and branch number differences between populations.
Collapse
Affiliation(s)
- Robert L Baker
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, 80309, USA.
| | | |
Collapse
|
31
|
Quantitative trait locus analysis of stage-specific inbreeding depression in the Pacific oyster Crassostrea gigas. Genetics 2011; 189:1473-86. [PMID: 21940682 DOI: 10.1534/genetics.111.131854] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Inbreeding depression and genetic load have been widely observed, but their genetic basis and effects on fitness during the life cycle remain poorly understood, especially for marine animals with high fecundity and high, early mortality (type-III survivorship). A high load of recessive mutations was previously inferred for the Pacific oyster Crassostrea gigas, from massive distortions of zygotic, marker segregation ratios in F(2) families. However, the number, genomic location, and stage-specific onset of mutations affecting viability have not been thoroughly investigated. Here, we again report massive distortions of microsatellite-marker segregation ratios in two F(2) hybrid families, but we now locate the causative deleterious mutations, using a quantitative trait locus (QTL) interval-mapping model, and we characterize their mode of gene action. We find 14-15 viability QTL (vQTL) in the two families. Genotypic frequencies at vQTL generally suggest selection against recessive or partially recessive alleles, supporting the dominance theory of inbreeding depression. No epistasis was detected among vQTL, so unlinked vQTL presumably have independent effects on survival. For the first time, we track segregation ratios of vQTL-linked markers through the life cycle, to determine their stage-specific expression. Almost all vQTL are absent in the earliest life stages examined, confirming zygotic viability selection; vQTL are predominantly expressed before the juvenile stage (90%), mostly at metamorphosis (50%). We estimate that, altogether, selection on vQTL caused 96% mortality in these families, accounting for nearly all of the actual mortality. Thus, genetic load causes substantial mortality in inbred Pacific oysters, particularly during metamorphosis, a critical developmental transition warranting further investigation.
Collapse
|
32
|
MARRIAGE TN, KELLY JK. Inbreeding depression in an asexual population ofMimulus guttatus. J Evol Biol 2009; 22:2320-31. [DOI: 10.1111/j.1420-9101.2009.01848.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
33
|
Effects of herkogamy and inbreeding on the mating system of Mimulus luteus in the absence of pollinators. Evol Ecol 2009. [DOI: 10.1007/s10682-009-9322-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
34
|
Fox CW, Scheibly KL, Reed DH. EXPERIMENTAL EVOLUTION OF THE GENETIC LOAD AND ITS IMPLICATIONS FOR THE GENETIC BASIS OF INBREEDING DEPRESSION. Evolution 2008; 62:2236-49. [DOI: 10.1111/j.1558-5646.2008.00441.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
35
|
Kelly JK. Testing the rare-alleles model of quantitative variation by artificial selection. Genetica 2008; 132:187-98. [PMID: 17607507 PMCID: PMC2682333 DOI: 10.1007/s10709-007-9163-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2006] [Accepted: 06/09/2007] [Indexed: 10/23/2022]
Abstract
The rare-alleles model of quantitative variation posits that a common allele (the 'wild-type') and one or more rare alleles segregate at each locus affecting a quantitative trait; a scenario predicted by several distinct evolutionary hypotheses. Single locus arguments suggest that artificial selection should substantially increase the genetic variance (Vg) if the rare-alleles model is accurate. This paper tests the 'DeltaVg prediction' using a large artificial selection experiment on flower size of Mimulus guttatus. Vg for flower size does evolve, increasing with selection for larger flower while decreasing in the other direction. These data are consistent with a model in which flower size variation is caused by rare, partially dominant alleles. However, this explanation becomes increasingly tenuous when considered with other data (correlated responses to selection and the effects of inbreeding). A combination of modern (marker-based mapping) and classical (biometric) techniques will likely to be required to determine the distribution of allele frequencies at loci influencing quantitative traits.
Collapse
Affiliation(s)
- John K Kelly
- Department of Ecology and Evolutionary Biology, University of Kansas, 1200 Sunnyside Ave, Lawrence, KS, 66045-7534, USA.
| |
Collapse
|
36
|
Mena-Ali JI, Keser LH, Stephenson AG. Inbreeding depression in Solanum carolinense (Solanaceae), a species with a plastic self-incompatibility response. BMC Evol Biol 2008; 8:10. [PMID: 18199336 PMCID: PMC2244599 DOI: 10.1186/1471-2148-8-10] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2007] [Accepted: 01/16/2008] [Indexed: 11/29/2022] Open
Abstract
Background Solanum carolinense (horsenettle) is a highly successful weed with a gametophytic self-incompatibility (SI) system. Previous studies reveal that the strength of SI in S. carolinense is a plastic trait, associated with particular S-alleles. The importance of this variation in self-fertility on the ability of horsenettle to found and establish new populations will depend, to a large extent, on the magnitude of inbreeding depression. We performed a series of greenhouse and field experiments to determine the magnitude of inbreeding depression in S. carolinense, whether inbreeding depression varies by family, and whether the estimates of inbreeding depression vary under field and greenhouse conditions. We performed a series of controlled self- and cross-pollinations on 16 genets collected from a large population in Pennsylvania to obtain progeny with different levels of inbreeding. We grew the selfed and outcrossed progeny in the greenhouse and under field conditions and recorded various measures of growth and reproductive output. Results In the greenhouse study we found (1) a reduction in flower, fruit and seed production per fruit in inbred (selfed) progeny when compared to outbred (outcrossed) progeny; (2) a reduction in growth of resprouts obtained from rhizome cuttings of selfed progeny; and (3) an increase in the ability to self-fertilize in the selfed progeny. In the field, we found that (1) outcrossed progeny produced more leaves than their selfed siblings; (2) herbivory seems to add little to inbreeding depression; and (3) outcrossed plants grew faster and were able to set more fruits than selfed plants. Conclusion Solanum carolinense experiences low levels of inbreeding depression under greenhouse conditions and slightly more inbreeding depression under our field conditions. The combined effects of low levels of inbreeding depression and plasticity in the strength of SI suggest that the production of selfed progeny may play an important role in the establishment of new populations of S. carolinense.
Collapse
Affiliation(s)
- Jorge I Mena-Ali
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA.
| | | | | |
Collapse
|
37
|
Evanno G, Castella E, Goudet J. Evolutionary aspects of population structure for molecular and quantitative traits in the freshwater snail Radix balthica. J Evol Biol 2006; 19:1071-82. [PMID: 16780508 DOI: 10.1111/j.1420-9101.2006.01098.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Detecting the action of selection in natural populations can be achieved using the QST-FST comparison that relies on the estimation of FST with neutral markers, and QST using quantitative traits potentially under selection. QST higher than FST suggests the action of directional selection and thus potential local adaptation. In this article, we apply the QST-FST comparison to four populations of the hermaphroditic freshwater snail Radix balthica located in a floodplain habitat. In contrast to most studies published so far, we did not detect evidence of directional selection for local optima for any of the traits we measured: QST calculated using three different methods was never higher than FST. A strong inbreeding depression was also detected, indicating that outcrossing is probably predominant over selfing in the studied populations. Our results suggest that in this floodplain habitat, local adaptation of R. balthica populations may be hindered by genetic drift, and possibly altered by uneven gene flow linked to flood frequency.
Collapse
Affiliation(s)
- G Evanno
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.
| | | | | |
Collapse
|
38
|
Glaettli M, Goudet J. Inbreeding effects on progeny sex ratio and gender variation in the gynodioecious Silene vulgaris (Caryophyllaceae). THE NEW PHYTOLOGIST 2006; 172:763-73. [PMID: 17096801 DOI: 10.1111/j.1469-8137.2006.01866.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In gynodioecious species, sex expression is generally determined through cytoplasmic male sterility genes interacting with nuclear restorers of the male function. With dominant restorers, there may be an excess of females in the progeny of self-fertilized compared with cross-fertilized hermaphrodites. Moreover, the effect of inbreeding on late stages of the life cycle remains poorly explored. Here, we used hermaphrodites of the gynodioecious Silene vulgaris originating from three populations located in different valleys in the Alps to investigate the effects of two generations of self- and cross-fertilization on sex ratio and gender variation. We detected an increase in females in the progeny of selfed compared with outcrossed hermaphrodites and inbreeding depression for female and male fertility. Male fertility correlated positively with sex ratio differences between outbred and inbred progeny, suggesting that dominant restorers are likely to influence male fertility qualitatively and quantitatively in S. vulgaris. We argue that the excess of females in the progeny of selfed compared with outcrossed hermaphrodites and inbreeding depression for gamete production may contribute to the maintenance of females in gynodioecious populations of S. vulgaris because purging of the genetic load is less likely to occur.
Collapse
Affiliation(s)
- Mélanie Glaettli
- Department of Ecology and Evolution, 25 Willcocks Street, University of Toronto, Toronto, Ontario, Canada M5S 3B2.
| | | |
Collapse
|
39
|
Hall MC, Willis JH. DIVERGENT SELECTION ON FLOWERING TIME CONTRIBUTES TO LOCAL ADAPTATION IN MIMULUS GUTTATUS POPULATIONS. Evolution 2006. [DOI: 10.1554/05-688.1] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
40
|
Hall MC, Basten CJ, Willis JH. Pleiotropic quantitative trait loci contribute to population divergence in traits associated with life-history variation in Mimulus guttatus. Genetics 2005; 172:1829-44. [PMID: 16361232 PMCID: PMC1456280 DOI: 10.1534/genetics.105.051227] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Evolutionary biologists seek to understand the genetic basis for multivariate phenotypic divergence. We constructed an F2 mapping population (N = 539) between two distinct populations of Mimulus guttatus. We measured 20 floral, vegetative, and life-history characters on parents and F1 and F2 hybrids in a common garden experiment. We employed multitrait composite interval mapping to determine the number, effect, and degree of pleiotropy in quantitative trait loci (QTL) affecting divergence in floral, vegetative, and life-history characters. We detected 16 QTL affecting floral traits; 7 affecting vegetative traits; and 5 affecting selected floral, vegetative, and life-history traits. Floral and vegetative traits are clearly polygenic. We detected a few major QTL, with all remaining QTL of small effect. Most detected QTL are pleiotropic, implying that the evolutionary shift between these annual and perennial populations is constrained. We also compared the genetic architecture controlling floral trait divergence both within (our intraspecific study) and between species, on the basis of a previously published analysis of M. guttatus and M. nasutus. Eleven of our 16 floral QTL map to approximately the same location in the interspecific map based on shared, collinear markers, implying that there may be a shared genetic basis for floral divergence within and among species of Mimulus.
Collapse
Affiliation(s)
- Megan C Hall
- Department of Biology, Duke University, Durham, North Carolina 27708, USA.
| | | | | |
Collapse
|
41
|
Abstract
Epistasis contributes significantly to intrapopulation variation in floral morphology, development time, and male fitness components of Mimulus guttatus. This is demonstrated with a replicated line-cross experiment involving slightly over 7000 plants. The line-cross methodology is based on estimates for means. It thus has greater power than the variance partitioning approaches historically used to estimate epistasis within populations. The replication of the breeding design across many pairs of randomly extracted, inbred lines is necessary given the diversity of multilocus genotypes residing within an outbred deme. Male fitness is shown to exhibit synergistic epistasis, an accelerating decline in fitness with inbreeding. Synergism is a necessary, but not sufficient, condition for a mutational deterministic hypothesis for the evolutionary maintenance of sexual reproduction. Unlike male fitness measures, flower morphology and development time yield positive evidence of epistasis but not of synergism. The results for these traits suggest that epistatic effects are variable across genetic backgrounds or sets of interacting loci.
Collapse
Affiliation(s)
- John K Kelly
- Department of Ecology and Evolutionary Biology, University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045, USA.
| |
Collapse
|
42
|
Heschel MS, Hausmann N, Schmitt J. Testing for stress-dependent inbreeding depression in Impatiens capensis (Balsaminaceae). AMERICAN JOURNAL OF BOTANY 2005; 92:1322-1329. [PMID: 21646152 DOI: 10.3732/ajb.92.8.1322] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The relevance of inbreeding depression to the persistence of plant populations can depend upon whether stress magnifies inbreeding depression for fitness-related traits. To examine whether drought stress exacerbates inbreeding depression in gas exchange traits and biomass, we grew selfed and outcrossed progeny of inbred lines from two populations of Impatiens capensis in a greenhouse experiment under water-limited and moist soil conditions. Drought stress did not magnify the degree of inbreeding depression for any of the traits measured. In fact, in one population there was a trend for stronger inbreeding depression under well-watered, benign conditions. Furthermore, significant inbreeding depression for carbon assimilation rate and stomatal conductance was only detected in the lines from one population. In contrast, inbreeding depression for biomass was detected within both populations and differed among lines. Drought stress exerted significant selection on physiological traits, favoring increased carbon assimilation rates and decreased stomatal conductance in drought-stressed plants. Patterns of selection did not differ between inbred and outcrossed plants but did differ marginally between populations. Thus, estimates of selection were not biased by the mixed mating system per se, but may be biased by combining individuals from populations with different histories of selection and inbreeding.
Collapse
Affiliation(s)
- M Shane Heschel
- Department of Ecology and Evolutionary Biology, Brown University, Box G-W, Providence, Rhode Island 02912 USA
| | | | | |
Collapse
|
43
|
Rosa JM, Camacho S, García-Dorado A. A measure of the within-chromosome synergistic epistasis for Drosophila viability. J Evol Biol 2005; 18:1130-7. [PMID: 16033587 DOI: 10.1111/j.1420-9101.2005.00892.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In order to detect possible synergistic epistasis for viability in Drosophila melanogaster we assayed the relative viability of chromosomes II in: (i) panmixia, (ii) forced total homozygosity, and (iii) homozygosity for, on the average, half of their loci. As these genotypes were constructed using exactly the same set of chromosomes in the three cases, the design allows us to estimate the inbreeding depression rate at two different inbreeding levels in the absence of purging natural selection. Overall, no consistent synergistic epistasis was found. However, there was a small fraction of chromosomes whose severely deleterious effect when homozygous was almost significantly larger than expected from their viability when homozygous for half of their loci. This suggests occasional but important synergistic epistasis, which might confer evolutionary advantage to recombination in tightly linked genomes. Nevertheless, such epistasis is unlikely to be an evolutionary advantage driving the evolution of sexual anisogamous reproduction, as its contribution to overall viability is small when compared with the two-fold cost of anisogamy.
Collapse
Affiliation(s)
- J M Rosa
- Departamento de Genética, Facultad de Biología, Universidad Complutense de Madrid, Madrid, Spain
| | | | | |
Collapse
|
44
|
Hall MC, Willis JH. Transmission ratio distortion in intraspecific hybrids of Mimulus guttatus: implications for genomic divergence. Genetics 2005; 170:375-86. [PMID: 15781698 PMCID: PMC1449724 DOI: 10.1534/genetics.104.038653] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2004] [Accepted: 02/07/2005] [Indexed: 11/18/2022] Open
Abstract
We constructed a genetic linkage map between two divergent populations of Mimulus guttatus. We genotyped an F(2) mapping population (N = 539) at 154 AFLP, microsatellite, and gene-based markers. A framework map was constructed consisting of 112 marker loci on 14 linkage groups with a total map length of 1518 cM Kosambi. Nearly half of all markers (48%) exhibited significant transmission ratio distortion (alpha = 0.05). By using a Bayesian multipoint mapping method and visual inspection of significantly distorted markers, we detected 12 transmission ratio distorting loci (TRDL) throughout the genome. The high degree of segregation distortion detected in this intraspecific map indicates substantial genomic divergence that perhaps suggests genomic incompatibilities between these two populations. We compare the pattern of transmission ratio distortion in this map to an interspecific map constructed between M. guttatus and M. nasutus. A similar level of segregation distortion is detected in both maps. Collinear regions between maps are compared to determine if there are shared genetic patterns of non-Mendelian segregation distortion within and among Mimulus species.
Collapse
Affiliation(s)
- Megan C Hall
- Department of Biology, Duke University, Durham, North Carolina 27708, USA.
| | | |
Collapse
|
45
|
Abstract
In this article, we study the effect of self-fertilization on the evolution of a modifier allele that alters the recombination rate between two selected loci. We consider two different life cycles: under gametophytic selfing, a given proportion of fertilizations involves gametes produced by the same haploid individual, while under sporophytic selfing, a proportion of fertilizations involves gametes produced by the same diploid individual. Under both life cycles, we derive approximations for the change in frequency of the recombination modifier when selection is weak relative to recombination, so that the population reaches a state of quasi-linkage equilibrium. We find that gametophytic selfing increases the range of epistasis under which increased recombination is favored; however, this effect is substantial only for high selfing rates. Moreover, gametophytic selfing affects the relative influence of different components of epistasis (additive x additive, additive x dominance, dominance x dominance) on the evolution of the modifier. Sporophytic selfing has much stronger effects: even a small selfing rate greatly increases the parameter range under which recombination is favored, when there is negative dominance x dominance epistasis. This effect is due to the fact that selfing generates a correlation in homozygosity at linked loci, which is reduced by recombination.
Collapse
Affiliation(s)
- Denis Roze
- Génétique et Evolution des Maladies Infectieuses, Institut de Recherche Pour le Développement, Montpellier, France.
| | | |
Collapse
|
46
|
Kleunen M, Ritland K. Predicting evolution of floral traits associated with mating system in a natural plant population. J Evol Biol 2005; 17:1389-99. [PMID: 15525423 DOI: 10.1111/j.1420-9101.2004.00787.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Evolution of floral traits requires that they are heritable, that they affect fitness, and that they are not constrained by genetic correlations. These prerequisites have only rarely been examined in natural populations. For Mimulus guttatus, we found by using the Riska-method that corolla width, anther length, ovary length and number of red dots on the corolla were heritable in a natural population. Seed production (maternal fitness) was directly positively affected by corolla width and anther size, and indirectly so by ovary length and number of red dots on the corolla. The siring success (paternal fitness), as estimated from allozyme data, was directly negatively affected by anther-stigma separation, and indirectly so by the corolla length-width ratio. Genetic correlations, estimated with the Lynch-method, were positive between floral size measures. We predict that larger flowers with larger reproductive organs, which generally favour outcrossing, will evolve in this natural population of M. guttatus.
Collapse
Affiliation(s)
- M Kleunen
- Department of Forest Sciences, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
| | | |
Collapse
|
47
|
Hayes CN, Winsor JA, Stephenson AG. A comparison of male and female responses to inbreeding in Cucurbita pepo subsp. texana (Cucurbitaceae). AMERICAN JOURNAL OF BOTANY 2005; 92:107-115. [PMID: 21652390 DOI: 10.3732/ajb.92.1.107] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Accurate estimates of inbreeding depression are necessary in order to predict the evolutionary dynamics of a population, but many studies estimate inbreeding depression based solely on components of female function such as fruit set, seed set, and seed quality. Because total fitness is achieved through both male and female functions in hermaphroditic plants, estimates of both male and female fitness are needed to estimate accurately the magnitude of inbreeding depression. Seedlings of a wild gourd, Cucurbita pepo subsp. texana, with coefficients of inbreeding of 0 and 0.75 were planted in an experimental garden, and several components of male and female fitness were measured over the course of the growing season. Fitness in inbred plants was confounded by both maternal and genetic inbreeding effects. Inbred individuals produced significantly fewer fruits than outcrossed individuals, and percentage germination of seeds from inbred individuals was significantly lower than seeds from outcrossed individuals. Inbred plants also produced significantly fewer staminate flowers and marginally fewer and smaller pollen grains per flower. Pollen from inbred plants also grew significantly more slowly in vitro than pollen from outcrossed plants. Multiplicative estimates of inbreeding depression revealed inbreeding depression for both male and female functions in wild gourd, but inbreeding depression through female function was stronger than inbreeding depression through male function.
Collapse
Affiliation(s)
- C Nelson Hayes
- Department of Biology, 208 Mueller Lab, The Pennsylvania State University, University Park, Pennsylvania 16802 USA
| | | | | |
Collapse
|
48
|
Hayes CN, Winsor JA, Stephenson AG. Environmental variation influences the magnitude of inbreeding depression in Cucurbita pepo ssp. texana (Cucurbitaceae). J Evol Biol 2005; 18:147-55. [PMID: 15669971 DOI: 10.1111/j.1420-9101.2004.00785.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We grew inbred and outcrossed Cucurbita pepo ssp. texana plants and measured inbreeding depression for several male and female fitness traits 4 years in a row in adjacent fields at the same field station under the same cultivation conditions. We found that the magnitude of inbreeding depression varied from 0.16 to 0.53 from year to year and that those traits which were most affected tended to vary with year. We also grew inbred and outcrossed C. pepo ssp. texana plants in two adjacent fields differing only in the presence of nitrogen fertilizer to examine the effect of nutrient limitation as a form of environmental stress on the magnitude of inbreeding depression. We found that inbreeding depression was more severe in the unfertilized field. Overall, this study illustrates the notion that any estimate of inbreeding depression represents a single point in a cluster of possible estimates that can vary (often dramatically) with growing conditions.
Collapse
Affiliation(s)
- C Nelson Hayes
- Department of Biology, 208 Mueller Lab, The Pennsylvania State University, University Park, PA 16802, USA.
| | | | | |
Collapse
|
49
|
Hayes CN, Winsor JA, Stephenson AG. MULTIGENERATIONAL EFFECTS OF INBREEDING IN CUCURBITA PEPO SSP. TEXANA (CUCURBITACEAE). Evolution 2005. [DOI: 10.1554/03-740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
50
|
MASUDA M, YAHARA T, MAKI M. Evolution of floral dimorphism in a cleistogamous annual,Impatiens noli-tangereL. occurring under different environmental conditions. Ecol Res 2004. [DOI: 10.1111/j.1440-1703.2004.00673.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|