Analyses of pairwise relatedness represent a key component to addressing many topics in biology. However, such analyses have been limited because most available programs provide a means to estimate relatedness based on only a single estimator, making comparison across estimators difficult. Second, all programs to date have been platform specific, working only on a specific operating system. This has the undesirable outcome of making choice of relatedness estimator limited by operating system preference, rather than being based on scientific rationale. Here, we present a new R package, called related, that can calculate relatedness based on seven estimators, can account for genotyping errors, missing data and inbreeding, and can estimate 95% confidence intervals. Moreover, simulation functions are provided that allow for easy comparison of the performance of different estimators and for analyses of how much resolution to expect from a given data set. Because this package works in R, it is platform independent. Combined, this functionality should allow for more appropriate analyses and interpretation of pairwise relatedness and will also allow for the integration of relatedness data into larger R workflows.
Recent speciation events provide important insights into the understanding and conservation of Earth's biodiversity, representing recent adaptations to a changing environment and an important source of future evolutionary potential. However, the most frequently applied criterion for molecularbased speciation investigations, that of reciprocal monophyly of mitochondrial sequences, overlooks recent speciation events where insufficient time has passed for fixed molecular differences to develop between putative species. Two morphologically distinguishable forms of finless porpoise (genus Neophocaena) exist in sympatry in the strait of Taiwan, however the taxonomic relationship of these different forms is controversial. To test the hypothesis that the two forms represent different species, a study was conducted based on morphological characters and microsatellite and mitochondrial markers. The data suggest that the two forms are highly differentiated in terms of both morphology and genetic characteristics, despite being sympatric, and therefore represent different species as defined by the biological species concept. Moreover, the two forms appear to have been reproductively isolated since sharing a common ancestor prior to the last major glaciation event B18 000 years ago. However, this represents an insufficient amount of time for reciprocal monophyly to have developed, and thus previous studies based on this criterion have overlooked this speciation event and resulted in incorrect taxonomic classification of these forms.
Storm is a software package that allows users to test a variety of hypotheses regarding patterns of relatedness and patterns of mate choice and/or mate compatibility within a population. These functions are based on four main calculations that can be conducted either independently or in the hypothesis-testing framework: internal relatedness; homozygosity by loci; pairwise relatedness; and a new metric called allele inheritance, which calculates the proportion of loci at which an offspring inherits a paternal allele different from that inherited from its mother. STORM allows users to test four hypotheses based on these calculations and Monte Carlo simulations: (i) are individuals within observed associations or groupings more/less related than expected; (ii) do observed offspring have more/less genetic variability (based on internal relatedness or homozygosity by loci) than expected from the gene pool; (iii) are observed mating pairs more/less related than expected if mating is random with respect to relatedness; and (iv) do observed offspring inherit paternal alleles different from those inherited from the mother more/less often than expected based on Mendelian inheritance.
Characterizing movement dynamics and spatial aspects of gene flow within a species permits inference on population structuring. As patterns of structuring are products of historical and current demographics and gene flow, assessment of structure through time can yield an understanding of evolutionary dynamics acting on populations that are necessary to inform management. Recent dramatic population declines in hibernating bats in eastern North America from white-nose syndrome have prompted the need for information on movement dynamics for multiple bat species. We characterized population genetic structure of the little brown bat, Myotis lucifugus, at swarming sites in southeastern Canada using 9 nuclear microsatellites and a 292-bp region of the mitochondrial genome. Analyses of FST, ΦST, and Bayesian clustering (STRUCTURE) found weak levels of genetic structure among swarming sites for the nuclear and mitochondrial genome (Global FST = 0.001, P < 0.05, Global ΦST = 0.045, P < 0.01, STRUCTURE K = 1) suggesting high contemporary gene flow. Hierarchical AMOVA also suggests little structuring at a regional (provincial) level. Metrics of nuclear genetic structure were not found to differ between males and females suggesting weak asymmetries in gene flow between the sexes. However, a greater degree of mitochondrial structuring does support male-biased dispersal long term. Demographic analyses were consistent with past population growth and suggest a population expansion occurred from approximately 1250 to 12,500 BP, following Pleistocene deglaciation in the region. Our study suggests high gene flow and thus a high degree of connectivity among bats that visit swarming sites whereby mainland areas of the region may be best considered as one large gene pool for management and conservation.
The eastern North Pacific gray whale Eschrichtius robustus was removed from the US Endangered Species List in 1994, and since then aboriginal groups in Washington (USA) and British Columbia (Canada) have discussed the resumption of traditional whaling. In particular, the Makah are pursuing legal permission to resume their hunt. Although the majority of whales in this population migrate to summer feeding grounds in the Bering, Chukchi, and Beaufort Seas, a small number of individuals (~200) spend the summers feeding in the waters ranging from northern California to southeast Alaska. The relationship of these 'southern feeding group' whales to the rest of the population is unknown. This information is key to making appropriate management decisions, because these whales inhabit the waters directly adjacent to the aboriginal communities interested in resuming whaling. We compared mitochondrial sequence data from 40 southern feeding group individuals to sequences from 105 individuals representing the larger population. We found significant differences in haplotype frequencies between the 2 groups, with an estimated long-term rate of exchange between the groups being <<1%. Moreover, estimates of Θ (N e µ for mtDNA data, i.e. the probability of a mutation occurring within the population in each generation) were significantly different between the 2 groups, indicating that the maternal lineages of the southern feeding group represent a distinct seasonal subpopulation. Combined, these data show that the southern feeding group of gray whales qualifies as a separate management unit, which should be considered when making conservation decisions.
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