The process and consequences of hybridization are of interest to evolutionary biologists because of the importance of hybridization in understanding reproductive isolation, speciation, and the influence of introgression on population genetic structure. Recent studies of hybridization have been enhanced by the advent of sensitive, genetic marker-based techniques for inferring the degree of admixture occurring within individuals. Here we present a genetic marker-based analysis of hybridization in a large-bodied, long-lived mammal over multiple generations. We analysed patterns of hybridization between yellow baboons (Papio cynocephalus) and anubis baboons (Papio anubis) in a well-studied natural population in Amboseli National Park, Kenya, using genetic samples from 450 individuals born over the last 36 years. We assigned genetic hybrid scores based on genotypes at 14 microsatellite loci using the clustering algorithm implemented in STRUCTURE 2.0, and assessed the robustness of these scores by comparison to pedigree information and through simulation. The genetic hybrid scores showed generally good agreement with previous morphological assessments of hybridity, but suggest that genetic methods may be more

Recent evidence from the genomic variation of living people documents genetic contributions from archaic to later modern humans. This evidence of introgression contrasts with earlier findings from single loci that appeared to exclude archaic human genetic survival. The present evidence indicates that many “archaic ” alleles may represent relicts of African archaics, and that some “archaic ” variants both inside and outside of Africa have attained relatively high frequencies. Both observations may be surprising under the hypothesis that modern humans originated first in Africa and displaced archaic populations through expansion and drift. Here, we outline how natural selection may have enabled the uptake of introgressive alleles from archaic humans. Even if admixture or gene flow were minimal, the introgression of selected variants would have been highly probable. In contrast to neutral alleles, adaptive alleles may attain high frequencies after minimal genetic introgression. Adaptive introgression can therefore explain why some loci show evidence for some archaic human contribution even as others apparently exclude it. The dynamics of introgression also may explain the distribution of certain deep haplotype branches in Africa. Open questions remain, including the likelihood that archaic alleles retained their adaptive value on the genetic background of modern humans and the scope of functions influenced by adaptive introgression. How important is introgressive hybridization? I do not

Research article Speciation and phylogeography in the cosmopolitan marine moon

Research article Phenotypic novelty in experimental hybrids is predicted by the genetic distance between species of cichlid fish

host-parasite interactions in the Daphnia longispina hybrid complex

impact of interspecific hybridization in animals Since the time of Charles Darwin, studies of interspecific hybridization have been a major focus for evolutionary biologists. Although this phenomenon has often been viewed as problematic in the fields of ecology, taxonomy and systematics, it has become a primary source of data for studies on

Background. ‘‘Explosive’ ’ adaptive radiations on islands remain one of the most puzzling evolutionary phenomena. The rate of phenotypic and ecological adaptations is extremely fast during such events, suggesting that many genes may be under fairly strong selection. However, no evidence for adaptation at the level of protein coding genes was found, so it has been suggested that selection may work mainly on regulatory elements. Here we report the first evidence that positive selection does operate at the level of protein coding genes during rapid adaptive radiations. We studied molecular adaptation in Hawaiian endemic plant genus Schiedea (Caryophyllaceae), which includes closely related species with a striking range of morphological and ecological forms, varying from rainforest vines to woody shrubs growing in desert-like conditions on cliffs. Given the remarkable difference in photosynthetic performance between Schiedea species from different habitats, we focused on the ‘‘photosynthetic’ ’ Rubisco enzyme, the efficiency of which is known to be a limiting step in plant photosynthesis. Results. We demonstrate that the chloroplast rbcL gene, encoding the large subunit of Rubisco enzyme, evolved under strong positive selection in Schiedea. Adaptive amino acid changes occurred in functionally important regions of Rubisco that interact with Rubisco activase, a chaperone which promotes and maintains the catalytic activity of Rubisco. Interestingly, positive selection acting on the rbcL might have caused favorable cytotypes to spread across several Schiedea species. Significance. We report the first evidence for adaptive changes at the DNA and protein sequence level that may have been associated with the evolution of photosynthetic performance and colonization of new habitats during a recent adaptive radiation in an island