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- Joshi, Peter K, et al.
(författare)
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Directional dominance on stature and cognition in diverse human populations
- 2015
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 523:7561, s. 459-462
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Tidskriftsartikel (refereegranskat)abstract
- Homozygosity has long been associated with rare, often devastating, Mendelian disorders, and Darwin was one of the first to recognize that inbreeding reduces evolutionary fitness. However, the effect of the more distant parental relatedness that is common in modern human populations is less well understood. Genomic data now allow us to investigate the effects of homozygosity on traits of public health importance by observing contiguous homozygous segments (runs of homozygosity), which are inferred to be homozygous along their complete length. Given the low levels of genome-wide homozygosity prevalent in most human populations, information is required on very large numbers of people to provide sufficient power. Here we use runs of homozygosity to study 16 health-related quantitative traits in 354,224 individuals from 102 cohorts, and find statistically significant associations between summed runs of homozygosity and four complex traits: height, forced expiratory lung volume in one second, general cognitive ability and educational attainment (P < 1 × 10(-300), 2.1 × 10(-6), 2.5 × 10(-10) and 1.8 × 10(-10), respectively). In each case, increased homozygosity was associated with decreased trait value, equivalent to the offspring of first cousins being 1.2 cm shorter and having 10 months' less education. Similar effect sizes were found across four continental groups and populations with different degrees of genome-wide homozygosity, providing evidence that homozygosity, rather than confounding, directly contributes to phenotypic variance. Contrary to earlier reports in substantially smaller samples, no evidence was seen of an influence of genome-wide homozygosity on blood pressure and low density lipoprotein cholesterol, or ten other cardio-metabolic traits. Since directional dominance is predicted for traits under directional evolutionary selection, this study provides evidence that increased stature and cognitive function have been positively selected in human evolution, whereas many important risk factors for late-onset complex diseases may not have been.
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| 2. |
- Dey, Cody J., et al.
(författare)
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Direct benefits and evolutionary transitions to complex societies
- 2017
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Ingår i: Nature Ecology and Evolution. - : Springer Science and Business Media LLC. - 2397-334X. ; 1:5
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Tidskriftsartikel (refereegranskat)abstract
- The selective forces that drive the evolution of cooperation have been intensely debated. Evolutionary transitions to cooperative breeding, a complex form of cooperation, have been hypothesized to be linked to low degrees of promiscuity, which increases intragroup relatedness and the indirect (that is, kin selected) benefits of helping. However, ecological factors also promote cooperative breeding, and may be more important than relatedness in some contexts. Identifying the key evolutionary drivers of cooperative breeding therefore requires an integrated assessment of these hypotheses. Here we show, using a phylogenetic framework that explicitly evaluates mating behaviours and ecological factors, that evolutionary transitions to cooperative breeding in cichlid fishes were not associated with social monogamy. Instead, group living, biparental care and diet type directly favoured the evolution of cooperative breeding. Our results suggest that cichlid fishes exhibit an alternative path to the evolution of complex societies compared to other previously studied vertebrates, and these transitions are driven primarily by direct fitness benefits.
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