Fitness consequences of cousin marriage: a life-history assessment in two populations
Cousin marriage, a spousal union between close kin, occurs at high frequencies in many parts of the world. The rates of cousin marriage in humans are concordant with empirical studies that challenge the traditionally held view that reproduction with kin is generally avoided in animals. Similarly, so...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2023-01-01
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| Series: | Evolutionary Human Sciences |
| Subjects: | |
| Online Access: | https://www.cambridge.org/core/product/identifier/S2513843X2200055X/type/journal_article |
| _version_ | 1827795745026080768 |
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| author | Arianna Dalzero Cody T. Ross Dieter Lukas |
| author_facet | Arianna Dalzero Cody T. Ross Dieter Lukas |
| author_sort | Arianna Dalzero |
| collection | DOAJ |
| description | Cousin marriage, a spousal union between close kin, occurs at high frequencies in many parts of the world. The rates of cousin marriage in humans are concordant with empirical studies that challenge the traditionally held view that reproduction with kin is generally avoided in animals. Similarly, some theoretical models in animal behaviour show that inbreeding avoidance is more constrained than previously thought. Such studies highlight the importance of quantifying the costs and benefits of reproduction among close kin over the whole life-course. Here, we use genealogical data from two human populations with high frequencies of cousin marriage (the Dogon from Mali, and the Ancien Régime nobility from Europe) to estimate these potential costs and benefits. We compare age-specific fertility and survival curves, as well as the projected growth rates, of subpopulations of each marriage type. Fitness costs of cousin marriage are present in terms of reduced child survival (in both populations), while benefits exist as increased fertility for men (in the Dogon) and for women (in the Ancien Régime nobility). We also find some differences in the projected growth rates of lineages as a function of marriage type. Finally, we discuss the trade-offs that might shape marriage decisions in different ecological conditions. |
| first_indexed | 2024-03-11T18:54:49Z |
| format | Article |
| id | doaj.art-9bbe375540b4481490af5a231bb84189 |
| institution | Directory Open Access Journal |
| issn | 2513-843X |
| language | English |
| last_indexed | 2024-03-11T18:54:49Z |
| publishDate | 2023-01-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Evolutionary Human Sciences |
| spelling | doaj.art-9bbe375540b4481490af5a231bb841892023-10-11T06:14:32ZengCambridge University PressEvolutionary Human Sciences2513-843X2023-01-01510.1017/ehs.2022.55Fitness consequences of cousin marriage: a life-history assessment in two populationsArianna Dalzero0https://orcid.org/0000-0002-3499-4272Cody T. Ross1Dieter Lukas2Department of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, GermanyDepartment of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, GermanyDepartment of Human Behavior, Ecology and Culture, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, GermanyCousin marriage, a spousal union between close kin, occurs at high frequencies in many parts of the world. The rates of cousin marriage in humans are concordant with empirical studies that challenge the traditionally held view that reproduction with kin is generally avoided in animals. Similarly, some theoretical models in animal behaviour show that inbreeding avoidance is more constrained than previously thought. Such studies highlight the importance of quantifying the costs and benefits of reproduction among close kin over the whole life-course. Here, we use genealogical data from two human populations with high frequencies of cousin marriage (the Dogon from Mali, and the Ancien Régime nobility from Europe) to estimate these potential costs and benefits. We compare age-specific fertility and survival curves, as well as the projected growth rates, of subpopulations of each marriage type. Fitness costs of cousin marriage are present in terms of reduced child survival (in both populations), while benefits exist as increased fertility for men (in the Dogon) and for women (in the Ancien Régime nobility). We also find some differences in the projected growth rates of lineages as a function of marriage type. Finally, we discuss the trade-offs that might shape marriage decisions in different ecological conditions.https://www.cambridge.org/core/product/identifier/S2513843X2200055X/type/journal_articleMating systemscousin marriagelife-historydemographykinship |
| spellingShingle | Arianna Dalzero Cody T. Ross Dieter Lukas Fitness consequences of cousin marriage: a life-history assessment in two populations Evolutionary Human Sciences Mating systems cousin marriage life-history demography kinship |
| title | Fitness consequences of cousin marriage: a life-history assessment in two populations |
| title_full | Fitness consequences of cousin marriage: a life-history assessment in two populations |
| title_fullStr | Fitness consequences of cousin marriage: a life-history assessment in two populations |
| title_full_unstemmed | Fitness consequences of cousin marriage: a life-history assessment in two populations |
| title_short | Fitness consequences of cousin marriage: a life-history assessment in two populations |
| title_sort | fitness consequences of cousin marriage a life history assessment in two populations |
| topic | Mating systems cousin marriage life-history demography kinship |
| url | https://www.cambridge.org/core/product/identifier/S2513843X2200055X/type/journal_article |
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