Browsing by Author "Barrowclough, George F."
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Item Hybrid origin of a unisexual species of whiptail lizard, Cnemidophorus neomexicanus, in western North America : new evidence and a review. American Museum novitates ; ; no. 2905.(New York, N.Y. : American Museum of Natural History, 1988) Cole, Charles J.; Dessauer, Herbert C.; Barrowclough, George F.Item The mitochondrial genome of Allonautilus (Mollusca, Cephalopoda) : base composition, noncoding-region variation, and phylogenetic divergence. (American Museum novitates, no. 3834)(American Museum of Natural History., 2015-04-30) Groth, Jeffrey G.; Arbisser, Ilana.; Landman, Neil H.; Barrowclough, George F.We used next-generation methods to sequence the mitochondrial genome of Allonautilus scrobiculatus from two large, overlapping amplicons generated by PCR. The genome was circular, 16,132 base pairs in length, and possessed the same sequence and orientation of genes as the previously sequenced mitogenome of Nautilus macromphalus. These two mitogenomes were approximately 8% divergent overall, but differentiation varied greatly among genes: some tRNA sequences were identical between the two taxa, whereas ATP8 differed by over 15%. The largest of the noncoding regions of the genome included a 62 base pair repeat that was essentially identical between the two genera; however, this repeat was present as six copies in N. macromphalus, but varied between four and five among individuals of Allonautilus. A 146 base pair deletion (in Allonautilus compared to Nautilus) included one copy of the repeat plus an adjacent 84 bp; because of this indel, the "CA" microsatellite in N. macromphalus was missing from Allonautilus. Base composition varied along the Allonautilus sequence, and was correlated with the strand on which genes coded. Base composition also varied within the largest noncoding region. A phylogeny of 24 extant cephalopods indicates that there is less molecular divergence between Allonautilus and Nautilus than there is among congeneric species of Octopus and Sepia.Item Phylogeography, species limits, phylogeny, and classification of the turacos (Aves, Musophagidae) based on mitochondrial and nuclear DNA sequences. (American Museum novitates, no. 3949)(American Museum of Natural History., 2020-04-03) Perktaş, Utku.; Groth, Jeffrey G.; Barrowclough, George F.We used mitochondrial and nuclear DNA sequences to examine patterns of differentiation and evolution in the Musophagidae, an avian family endemic to sub-Saharan Africa; attention was focused on the subfamily Musophaginae, the turacos, or louries. Phylogeographic analysis of 410 individual ND2 sequences from throughout the ranges of the currently recognized species revealed multiple instances of unexpectedly large genetic divergences and cryptic taxa. Within both montane and lowland species, including Tauraco hartlaubi and T. schalowi, Menelikornis leucotis, Musophaga macrorhyncha, and Gallirex johnstoni, fixed private haplotypes were found in disjunct portions of the ranges, suggesting negligible recent gene flow and evolutionary independence of populations. Two taxa originally described as subspecies (T. schalowi loitanus and T. s. marungensis), but not recognized for over 50 years, were found to be 100% diagnosable based on the mitochondrial sequences. The data also revealed the existence of two polyphyletic traditional species, Tauraco livingstonii and T. schuettii, as well as the polyphyly or paraphyly of all traditional superspecies complexes involving members of the genus Tauraco. Overall, our analyses of genetic and morphological variation revealed substantial and unexpected geographic diversity within the Musophagidae. We recognize 33 species-level taxa that represent the appropriate units for phylogenetic and biogeographic analyses (phylogenetic species). We used complete mitochondrial ND2 sequences and nuclear DNA sequences of an Aconitase intron and of the RAG-1 exon to infer the phylogenetic relationships among those species. The results include all the phylogenetic species and, for the first time, nuclear data. We present a new classification of the Musophagidae based on our phylogeographic and phylogenetic results. We allocate the 33 species to seven previously recognized genera, an average of 4.7 species per genus.