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Pérez-Pereira N, Pouso R, Rus A, Vilas A, López-Cortegano E, García-Dorado A, Quesada H, Caballero A. Long-term exhaustion of the inbreeding load in Drosophila melanogaster. Heredity (Edinb) 2021; 127:373-383. [PMID: 34400819 PMCID: PMC8478893 DOI: 10.1038/s41437-021-00464-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 07/29/2021] [Accepted: 07/29/2021] [Indexed: 02/07/2023] Open
Abstract
Inbreeding depression, the decline in fitness of inbred individuals, is a ubiquitous phenomenon of great relevance in evolutionary biology and in the fields of animal and plant breeding and conservation. Inbreeding depression is due to the expression of recessive deleterious alleles that are concealed in heterozygous state in noninbred individuals, the so-called inbreeding load. Genetic purging reduces inbreeding depression by removing these alleles when expressed in homozygosis due to inbreeding. It is generally thought that fast inbreeding (such as that generated by full-sib mating lines) removes only highly deleterious recessive alleles, while slow inbreeding can also remove mildly deleterious ones. However, a question remains regarding which proportion of the inbreeding load can be removed by purging under slow inbreeding in moderately large populations. We report results of two long-term slow inbreeding Drosophila experiments (125-234 generations), each using a large population and a number of derived lines with effective sizes about 1000 and 50, respectively. The inbreeding load was virtually exhausted after more than one hundred generations in large populations and between a few tens and over one hundred generations in the lines. This result is not expected from genetic drift alone, and is in agreement with the theoretical purging predictions. Computer simulations suggest that these results are consistent with a model of relatively few deleterious mutations of large homozygous effects and partially recessive gene action.
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Affiliation(s)
- Noelia Pérez-Pereira
- grid.6312.60000 0001 2097 6738Centro de Investigación Mariña, Universidade de Vigo, Facultade de Bioloxía, Vigo, Spain
| | - Ramón Pouso
- grid.6312.60000 0001 2097 6738Centro de Investigación Mariña, Universidade de Vigo, Facultade de Bioloxía, Vigo, Spain
| | - Ana Rus
- grid.6312.60000 0001 2097 6738Centro de Investigación Mariña, Universidade de Vigo, Facultade de Bioloxía, Vigo, Spain
| | - Ana Vilas
- grid.6312.60000 0001 2097 6738Centro de Investigación Mariña, Universidade de Vigo, Facultade de Bioloxía, Vigo, Spain
| | - Eugenio López-Cortegano
- grid.6312.60000 0001 2097 6738Centro de Investigación Mariña, Universidade de Vigo, Facultade de Bioloxía, Vigo, Spain ,grid.4305.20000 0004 1936 7988Present Address: Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Aurora García-Dorado
- grid.4795.f0000 0001 2157 7667Facultad de Ciencias Biológicas, Departamento de Genética, Universidad Complutense, Madrid, Spain
| | - Humberto Quesada
- grid.6312.60000 0001 2097 6738Centro de Investigación Mariña, Universidade de Vigo, Facultade de Bioloxía, Vigo, Spain
| | - Armando Caballero
- grid.6312.60000 0001 2097 6738Centro de Investigación Mariña, Universidade de Vigo, Facultade de Bioloxía, Vigo, Spain
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López-Cortegano E, Pouso R, Labrador A, Pérez-Figueroa A, Fernández J, Caballero A. Optimal Management of Genetic Diversity in Subdivided Populations. Front Genet 2019; 10:843. [PMID: 31572448 PMCID: PMC6753960 DOI: 10.3389/fgene.2019.00843] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 08/13/2019] [Indexed: 11/29/2022] Open
Abstract
One of the main objectives of conservation programs is the maintenance of genetic diversity because this provides the adaptive potential of populations to face new environmental challenges. Genetic diversity is generally assessed by means of neutral molecular markers, and it is usually quantified by the expected heterozygosity under Hardy-Weinberg equilibrium and the number of alleles per locus or allelic diversity. These two measures of genetic diversity are complementary because whereas the former is directly related to genetic variance for quantitative traits and, therefore, to the short-term response to selection and adaptation, the latter is more sensitive to population bottlenecks and relates more strongly to the long-term capacity of adaptation of populations. In the context of structured populations undergoing conservation programs, it is important to decide the optimum management strategy to preserve as much genetic diversity as possible while avoiding inbreeding. Here we examine, through computer simulations, the consequences of choosing a conservation strategy based on maximizing either heterozygosity or allelic diversity of single-nucleotide polymorphism haplotypes in a subdivided population. Our results suggest that maximization of allelic diversity can be more efficient in maintaining the genetic diversity of subdivided populations than maximization of expected heterozygosity because the former maintains a larger number of alleles while making a better control of inbreeding. Thus, maximization of allelic diversity should be a recommended strategy in conservation programs for structured populations.
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Affiliation(s)
- Eugenio López-Cortegano
- Departamento de Bioquímica, Genética e Inmunología, Universidade de Vigo, Vigo, Spain.,Centro de Investigación Marina (CIM-UVIGO), Universidade de Vigo, Vigo, Spain
| | - Ramón Pouso
- Departamento de Bioquímica, Genética e Inmunología, Universidade de Vigo, Vigo, Spain.,Centro de Investigación Marina (CIM-UVIGO), Universidade de Vigo, Vigo, Spain
| | - Adriana Labrador
- Departamento de Bioquímica, Genética e Inmunología, Universidade de Vigo, Vigo, Spain.,Centro de Investigación Marina (CIM-UVIGO), Universidade de Vigo, Vigo, Spain
| | - Andrés Pérez-Figueroa
- Departamento de Bioquímica, Genética e Inmunología, Universidade de Vigo, Vigo, Spain
| | - Jesús Fernández
- Departamento de Mejora Genética, Instituto de Investigación y Tecnología Agraria y Alimentaria (INIA), Madrid, Spain
| | - Armando Caballero
- Departamento de Bioquímica, Genética e Inmunología, Universidade de Vigo, Vigo, Spain.,Centro de Investigación Marina (CIM-UVIGO), Universidade de Vigo, Vigo, Spain
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