Graph-structured populations and the Hill–Robertson effect
The Hill–Robertson effect describes how, in a finite panmictic diploid population, selection at one diallelic locus reduces the fixation probability of a selectively favoured allele at a second, linked diallelic locus. Here we investigate the influence of population structure on the Hill–Robertson e...
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| Format: | Article |
| Language: | English |
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The Royal Society
2021-03-01
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| Series: | Royal Society Open Science |
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| Online Access: | https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.201831 |
| _version_ | 1818363787223236608 |
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| author | Peter A. Whigham Hamish G. Spencer |
| author_facet | Peter A. Whigham Hamish G. Spencer |
| author_sort | Peter A. Whigham |
| collection | DOAJ |
| description | The Hill–Robertson effect describes how, in a finite panmictic diploid population, selection at one diallelic locus reduces the fixation probability of a selectively favoured allele at a second, linked diallelic locus. Here we investigate the influence of population structure on the Hill–Robertson effect in a population of size N. We model population structure as a network by assuming that individuals occupy nodes on a graph connected by edges that link members who can reproduce with each other. Three regular networks (fully connected, ring and torus), two forms of scale-free network and a star are examined. We find that (i) the effect of population structure on the probability of fixation of the favourable allele is invariant for regular structures, but on some scale-free networks and a star, this probability is greatly reduced; (ii) compared to a panmictic population, the mean time to fixation of the favoured allele is much greater on a ring, torus and linear scale-free network, but much less on power-2 scale-free and star networks; (iii) the likelihood with which each of the four possible haplotypes eventually fix is similar across regular networks, but scale-free populations and the star are consistently less likely and much faster to fix the optimal haplotype; (iv) increasing recombination increases the likelihood of fixing the favoured haplotype across all structures, whereas the time to fixation of that haplotype usually increased, and (v) star-like structures were overwhelmingly likely to fix the least fit haplotype and did so significantly more rapidly than other populations. Last, we find that small (N < 64) panmictic populations do not exhibit the scaling property expected from Hill & Robertson (1966 Genet. Res. 8, 269–294. (doi:10.1017/S0016672300010156)). |
| first_indexed | 2024-12-13T21:54:01Z |
| format | Article |
| id | doaj.art-1ddcc57768ec42bb9bb1d597837bc181 |
| institution | Directory Open Access Journal |
| issn | 2054-5703 |
| language | English |
| last_indexed | 2024-12-13T21:54:01Z |
| publishDate | 2021-03-01 |
| publisher | The Royal Society |
| record_format | Article |
| series | Royal Society Open Science |
| spelling | doaj.art-1ddcc57768ec42bb9bb1d597837bc1812022-12-21T23:30:12ZengThe Royal SocietyRoyal Society Open Science2054-57032021-03-018310.1098/rsos.201831201831Graph-structured populations and the Hill–Robertson effectPeter A. WhighamHamish G. SpencerThe Hill–Robertson effect describes how, in a finite panmictic diploid population, selection at one diallelic locus reduces the fixation probability of a selectively favoured allele at a second, linked diallelic locus. Here we investigate the influence of population structure on the Hill–Robertson effect in a population of size N. We model population structure as a network by assuming that individuals occupy nodes on a graph connected by edges that link members who can reproduce with each other. Three regular networks (fully connected, ring and torus), two forms of scale-free network and a star are examined. We find that (i) the effect of population structure on the probability of fixation of the favourable allele is invariant for regular structures, but on some scale-free networks and a star, this probability is greatly reduced; (ii) compared to a panmictic population, the mean time to fixation of the favoured allele is much greater on a ring, torus and linear scale-free network, but much less on power-2 scale-free and star networks; (iii) the likelihood with which each of the four possible haplotypes eventually fix is similar across regular networks, but scale-free populations and the star are consistently less likely and much faster to fix the optimal haplotype; (iv) increasing recombination increases the likelihood of fixing the favoured haplotype across all structures, whereas the time to fixation of that haplotype usually increased, and (v) star-like structures were overwhelmingly likely to fix the least fit haplotype and did so significantly more rapidly than other populations. Last, we find that small (N < 64) panmictic populations do not exhibit the scaling property expected from Hill & Robertson (1966 Genet. Res. 8, 269–294. (doi:10.1017/S0016672300010156)).https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.201831genetic driftnatural selectionpopulation structurefixationnetworkrecombination |
| spellingShingle | Peter A. Whigham Hamish G. Spencer Graph-structured populations and the Hill–Robertson effect Royal Society Open Science genetic drift natural selection population structure fixation network recombination |
| title | Graph-structured populations and the Hill–Robertson effect |
| title_full | Graph-structured populations and the Hill–Robertson effect |
| title_fullStr | Graph-structured populations and the Hill–Robertson effect |
| title_full_unstemmed | Graph-structured populations and the Hill–Robertson effect |
| title_short | Graph-structured populations and the Hill–Robertson effect |
| title_sort | graph structured populations and the hill robertson effect |
| topic | genetic drift natural selection population structure fixation network recombination |
| url | https://royalsocietypublishing.org/doi/pdf/10.1098/rsos.201831 |
| work_keys_str_mv | AT peterawhigham graphstructuredpopulationsandthehillrobertsoneffect AT hamishgspencer graphstructuredpopulationsandthehillrobertsoneffect |