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Allelic richness (number of alleles) is a measure of genetic diversity indicative of a population's long-term potential for adaptability and persistence. It is used less commonly than heterozygosity as a genetic diversity measure, partially because it is more mathematically difficult to take into account the stochastic process of genetic drift for allelic richness. This paper presents a stochastic model for the allelic richness of a newly founded population experiencing genetic drift and gene flow. The model follows the dynamics of alleles lost during the founder event and simulates the effect of gene flow on maintenance and recovery of allelic richness. The probability of an allele's presence in the population was identified as the relevant statistical property for a meaningful interpretation of allelic richness. A method is discussed that combines the probability of allele presence with a population's allele frequency spectrum to provide predictions for allele recovery. The model's analysis provides insights into the dynamics of allelic richness following a founder event, taking into account gene flow and the allele frequency spectrum. Furthermore, the model indicates that the "One Migrant per Generation" rule, a commonly used conservation guideline related to heterozygosity, may be inadequate for addressing preservation of diversity at the allelic level. This highlights the importance of distinguishing between heterozygosity and allelic richness as measures of genetic diversity, since focusing merely on the preservation of heterozygosity might not be enough to adequately preserve allelic richness, which is crucial for species persistence and evolution.

Understanding the dynamics of genetic structures which arise during a population's range expansion can be applied to the conservation of recovering species and species that are shifting their range. Theoretical models, supported by several empirical findings, have indicated that fine-scaled genetic structure can arise at the wave front of a spatially expanding population. We explored the development of population genetic structure in the reintroduced Asiatic wild ass ( Equus hemionus) in Israel, four generations after the onset of reintroduction, during which the population experienced demographic growth and range expansion over a complex landscape. Blood samples of the 'founding-population' and fecal samples of the 'wild-population', collected throughout the range of distribution were analyzed using mtDNA markers. Fecal samples were delimitated to 'subpopulations' according to their geographical locations. The 'East' subpopulation, at the wave front of the wild population's distribution, was found to be significantly different than the rest of the population (AMOVA, Φ = 0.13, P = 0.04). These findings were supported by an F-test, Spatial-AMOVA and a Barrier analysis. The 'East' region is characterized by high quality habitat patches and low landscape connectivity to the rest of the area, which possibly led to its relative isolation. The 'East' subpopulation was probably initiated following a founder-effect of dispersers from the release area, which remained in the 'new area', due to its high habitat quality. This genetic structure, though it might diminish over time due to gene flow and additional range expansion, has the potential of facilitating adaptive evolution and thereby affecting the population's long term persistence. [ABSTRACT FROM AUTHOR]

Highlights: [•] Races are highly genetically differentiated populations with sharp geographical boundaries. [•] Alternatively, races can be distinct evolutionary lineages within a species. [•] By either definition, races do not exist in humans but do exist in chimpanzees. [•] Adaptive traits such as skin color do not define races and are often discordant with one another. [•] Humans populations are interwoven by genetic interchanges; there is no tree of populations. [Copyright &y& Elsevier]

Eastern collared lizards of the Ozarks live in glades-open, rocky habitats embedded in a woodland matrix. Past fire suppression had made the woodlands a barrier to dispersal, leading to habitat destruction, fragmentation and local extinction. Reintroduced populations of lizards were subjected to 10 years of habitat fragmentation under continued fire suppression followed by twelve years of landscape restoration with prescribed burns. Prior to prescribed burning, genetic diversity decreased within glades and differentiation increased among glades. With woodland burning, genetic diversity within glades first decreased during an expanding colonization phase, but then increased as a dynamically stable metapopulation was established. Population differentiation among glades also stabilized in the metapopulation under weak isolation-by-distance. This study is one of the first to examine the genetic changes in a species of conservation concern throughout all the stages of decline and recovery and shows the importance of landscape-level restoration for maintaining the genetic integrity of populations. This study also demonstrates how mark-recapture and genetic data together can yield detailed insight into metapopulation dynamics that would be impossible from just one type of data alone. [ABSTRACT FROM AUTHOR]

A haplotype is a multisite haploid genotype at two or more polymorphic sites on the same chromosome in a defined DNA region. An evolutionary tree of the haplotypes can be estimated if the DNA region had little to no recombination. Haplotype trees can be used to reconstruct past human gene-flow patterns and historical events, but any single tree captures only a small portion of evolutionary history, and is subject to error. A fuller view of human evolution requires multiple DNA regions, and errors can be minimized by cross-validating inferences across loci. An analysis of 25 DNA regions reveals an out-of-Africa expansion event at 1.9 million years ago. Gene flow with isolation by distance was established between African and Eurasian populations by about 1.5 million years ago, with no detectable interruptions since. A second out-of-Africa expansion occurred about 700,000 years ago, and involved interbreeding with at least some Eurasian populations. A third out-of-Africa event occurred around 100,000 years ago, and was also characterized by interbreeding, with the hypothesis of a total Eurasian replacement strongly rejected (P < 10 17). This does not preclude the possibility that some Eurasian populations could have been replaced, and the status of Neanderthals is indecisive. Demographic inferences from haplotype trees have been inconsistent, so few definitive conclusions can be made at this time. Haplotype trees from human parasites offer additional insights into human evolution and raise the possibility of an Asian isolate of humanity, but once again not in a definitive fashion. Haplotype trees can also indicate which genes were subject to positive selection in the lineage leading to modern humans. Genetics provides many insights into human evolution, but those insights need to be integrated with fossil and archaeological data to yield a fuller picture of the origin of modern humans. [ABSTRACT FROM AUTHOR]