Binary polymorphisms associated with the non-recombining region of the human Y chromosome (NRY) preserve the paternal genetic legacy of our species that has persisted to the present, permitting inference of human evolution, population affinity and demographic history. We used denaturing high-performance liquid chromatography (DHPLC; ref. 2) to identify 160 of the 166 bi-allelic and 1 tri-allelic site that formed a parsimonious genealogy of 116 haplotypes, several of which display distinct population affinities based on the analysis of 1062 globally representative individuals. A minority of contemporary East Africans and Khoisan represent the descendants of the most ancestral patrilineages of anatomically modern humans that left Africa between 35,000 and 89,000 years ago.

A model of handedness incorporating both genetic and cultural processes is proposed, based on an evolutionary analysis, and maximum-likelihood estimates of its parameters are generated. This model has the characteristics that (i) no genetic variation underlies variation in handedness, and (ii) variation in handedness among humans is the result of a combination of cultural and developmental factors, but (iii) a genetic influence remains since handedness is a facultative trait. The model fits the data from 17 studies of handedness in families and 14 studies of handedness in monozygotic and dizygotic twins. This model has the additional advantages that it can explain why monozygotic and dizygotic twins and siblings have similar concordance rates, and no hypothetical selection regimes are required to explain the persistence of left handedness.

In a recent manuscript, Yang and colleagues criticized our paper, "Limitations of GCTA as a solution to the missing heritability problem". Here we show that their main claims are statistically invalid, and our results hold as stated.

In the first longitudinal study of bat microbiomes, we find that unlike the pattern described in humans and other mammals, the prominent dynamics in Egyptian fruit bats’ fur microbiomes are those of change over time at the level of the colony as a whole. Thus, on average, a pair of fur microbiome samples from different individuals in the same colony collected on the same date are more similar to one another than a pair of samples from the same individual collected at different time points. This pattern suggests that the whole colony may be the appropriate biological unit for understanding some of the roles of the host microbiome in social bats’ ecology and evolution. This pattern of synchronized colony changes over time is also reflected in the profile of volatile compounds in the bats’ fur, but differs from the more individualized pattern found in the bats’ gut microbiome.

Most natural populations are affected by seasonal changes in temperature, rainfall, or resource availability. Seasonally fluctuating selection could potentially make a large contribution to maintaining genetic polymorphism in populations. However, previous theory suggests that the conditions for multi-locus polymorphism are restrictive. Here we explore a more general class of models with multi-locus seasonally fluctuating selection in diploids.In these models, loci first contribute additively to a seasonal score, with a dominance parameter determining the relative contributions of heterozygous and homozygous loci. The seasonal score is then mapped to fitness via a monotonically increasing function, thereby accounting for epistasis. Using mathematical analysis and individual-based simulations, we show that stable polymorphism at many loci is possible if currently favored alleles are sufficiently dominant with respect to the additive seasonal score (but not necessarily with respect to fitness itself). This general mechanism, which we call "segregation lift", operates for various genotype-to-fitness maps and includes the previously known mechanism of multiplicative selection with marginal overdominance as a special case. We show that segregation lift may arise naturally in situations with antagonistic pleiotropy and 1 not peer-reviewed) is the author/funder. All rights reserved. No reuse allowed without permission.The copyright holder for this preprint (which was . http://dx.doi.org/10.1101/115444 doi: bioRxiv preprint first posted online Mar. 9, 2017; seasonal changes in the relative importance of traits for fitness. Segregation lift is not affected by problems of genetic load and is robust to differences in parameters across loci and seasons. Under segregation lift, loci can exhibit conspicuous seasonal allele-frequency fluctuations, but often fluctuations may also be small and hard to detect. Via segregation lift, seasonally fluctuating selection might contribute substantially to maintaining genetic variation in natural populations.Keywords temporal heterogeneity | cyclical selection | maintenance of genetic diversity | marginal overdominance | balancing selection