Anopheles funestus is a primary vector of malaria in Africa south of the Sahara. We assessed its rangewide population genetic structure based on samples from 11 countries, using 10 physically mapped microsatellite loci, two per autosome arm and the X (N = 548), and 834 bp of the mitochondrial ND5 gene (N = 470). On the basis of microsatellite allele frequencies, we found three subdivisions: eastern (coastal Tanzania, Malawi, Mozambique and Madagascar), western (Burkina Faso, Mali, Nigeria and western Kenya), and central (Gabon, coastal Angola). A. funestus from the southwest of Uganda had affinities to all three subdivisions. Mitochondrial DNA (mtDNA) corroborated this structure, although mtDNA gene trees showed less resolution. The eastern subdivision had significantly lower diversity, similar to the pattern found in the codistributed malaria vector Anopheles gambiae. This suggests that both species have responded to common geographic and/or climatic constraints. The western division showed signatures of population expansion encompassing Kenya west of the Rift Valley through Burkina Faso and Mali. This pattern also bears similarity to A. gambiae, and may reflect a common response to expanding human populations following the development of agriculture. Due to the presumed recent population expansion, the correlation between genetic and geographic distance was weak. Mitochondrial DNA revealed further cryptic subdivision in A. funestus, not detected in the nuclear genome. Mozambique and Madagascar samples contained two mtDNA lineages, designated clade I and clade II, that were separated by two fixed differences and an average of 2% divergence, which implies that they have evolved independently for approximately 1 million years. Clade I was found in all 11 locations, whereas clade II was sampled only on Madagascar and Mozambique. We suggest that the latter clade may represent mtDNA capture by A. funestus, resulting from historical gene flow either among previously isolated and divergent populations or with a related species.
Studies of population genetics increasingly use next-generation DNA sequencing to identify microsatellite loci in non-model organisms. There are, however, relatively few studies that validate the feasibility of transitioning from marker development to experimental application across populations and species. North American coralsnakes of the Micrurus fulvius species complex occur in the United States and Mexico, and little is known about their population structure and phylogenetic relationships. This absence of information and population genetics markers is particularly concerning because they are highly venomous and have important implications on human health. To alleviate this problem in coralsnakes, we investigated the feasibility of using 454 shotgun sequences for microsatellite marker development. First, a genomic shotgun library from a single individual was sequenced (~7.74 megabases; 26,831 reads) to identify potentially amplifiable microsatellite loci (PALs). We then hierarchically sampled 76 individuals from throughout the geographic distribution of the species complex and examined whether PALs were amplifiable and polymorphic. Approximately half of the loci tested were readily amplifiable from all individuals, and 80% of the loci tested for variation were variable and thus informative as population genetic markers. To evaluate the repetitive landscape characteristics across multiple snakes, we also compared microsatellite content between the coralsnake and two other previously sampled snakes, the venomous copperhead (Agkistrodon contortrix) and Burmese python (Python molurus).
While species boundaries between conspicuously divergent populations of the medically important snake genus Sinomicrurus are well established, instances of erratic chromatic and meristic variation continue to confound taxonomists, since the mid‐1800s. This predicament can be attributed to an inadequate molecular phylogenetic framework and the lack of a comprehensive taxonomic representation of geographic variants. Here, we revisit lineage delineation in this genus, drawing cohesive evidence from a plurality of data and analysis types, including a promising, yet taxonomically under‐utilized, supervised machine learning algorithm (random forest). Overall, this study incorporates data generated by molecular analyses as well as morphometrics and comparative anatomy based on 236 specimens from 28 different natural history collections examined by us, and an additional 161 records from 47 other sources. Our results indicate several very divergent evolutionary lineages concealed as subspecies. Thus, to better reflect this phylogenetic diversity, we raise S. macclellandi iwasakii from the southern Ryukyus and S. m. swinhoei from Taiwan to full species, and resurrect S. annularis. We highlight the need to distinguish at species level the current subspecies of S. japonicus, namely as, S. japonicus and S. boettgeri, and provide diagnostic characters to that end. On the other hand, given unpersuasive support of lineage independence, we sink Taiwanese S. hatori into S. sauteri and S. nigriventer into S. macclellandi. We also meticulously redescribe S. peinani from mainland China and Vietnam based on a substantial number of additional specimens, while synonymizing the recently described S. houi under S. kelloggi. We conclude with a discussion on the role of regional biogeography as a primary driver of cladogenesis in the genus.
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