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Sequence variation in the guillemot (Alcidae: Cepphus) mitochondrial control region and its nuclear homolog 总被引:4,自引:0,他引:4
We describe sequence variation in the mitochondrial control region and its
nuclear homolog in three species and seven subspecies of guillemots
(Cepphus spp.). Nuclear homologs of the 5' end of the control region were
found in all individuals. Nuclear sequences were approximately 50%
divergent from their mitochondrial counterparts and formed a distinct
phylogenetic clade; the mitochondrial-nuclear introgression event must have
predated the radiation of Cepphus. As in other vertebrates, the guillemot
control region has a relatively conserved central block flanked by
hypervariable 5' and 3' ends. Mean pairwise interspecific divergence values
among control regions were lower than those in other birds. All individuals
were heteroplasmic for the number of simple tandem nucleotide repeats
(A(n)C) at the 3' end of the control region. Phylogenetic analyses suggest
that black guillemots are basal to pigeon and spectacled guillemots, but
evolutionary relationships among subspecies remain unresolved, possibly due
to incomplete lineage sorting. Describing molecular variation in nuclear
homologs of mitochondrial genes is of general interest in phylogenetics
because, if undetected, the homologs may confound interpretations of
mitochondrial phylogenies.
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The aerobic gram positive bacterium Corynebacterium diphtheriae causes diphtheria, a respiratory tract illness characterized by symptoms such as sore throat, low fever, and an adherent membrane on the tonsils, pharynx, and/or nasal cavity. Therefore, it is important to develop preventive vaccines for diphtheria. The availability of the 2,488,635 bp long complete sequence for the C. diphtheriae genome provides an opportunity to understand cell mediated immune response using Computational Biology tools from the bacterial proteome sequence data. We selected 355 membrane proteins from the C. diphtheriae proteome using annotation data to identify potential HLA-DRB1 binding short peptide using modeling, simulations and predictions. This exercise identified 30 short peptides in membrane proteins showing binding capability to HLA-DRB1 alleles. These peptides serve as outline for the understanding of cell mediated immune response to C. diphtheriae. It should be noted that the predicted data to be verified using binding assays for further consideration. 相似文献
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François Clarac Thibaud Souter Raphaël Cornette Jorge Cubo Vivian de Buffrénil 《Journal of morphology》2015,276(10):1183-1192
Bone ornamentation, in the form of highly repetitive motives created by pits and ridges, is a frequent feature on vertebrate skull roofs and osteoderms. The functional significance of this character remains a matter of controversy and speculation. The many diverging hypotheses proposed to explain it all share a common logical prerequisite: bone ornamentation should increase significantly the surface area of the bones that bear it. In order to test this assumption in the Crocodylia, we developed a method for quantifying the gain in area due to ornamentation using a three‐dimensional‐surface scanner. On crocodylian osteoderms, the gain in area can be up to 40%, and on the cranial table, it ranges between 10 and 32% in adult specimens (in both cases, it shows substantial differences between the adults of the various species included in the sample). Area gain on the snout is lesser (0–20% in adults), and more variable between species. In general, bone ornamentation is less pronounced, and results in fewer area gains in juvenile specimens. The main morphometric results yielded by this study are discussed in reference to the few comparative data available hitherto, and to the functional interpretations proposed by previous authors. J. Morphol. 276:1183–1192, 2015. © 2015 Wiley Periodicals, Inc. 相似文献
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Elizabeth Tuck Jeanne Estabel Anika Oellrich Anna Karin Maguire Hibret A. Adissu Luke Souter Emma Siragher Charlotte Lillistone Angela L. Green Hannah Wardle-Jones Damian M. Carragher Natasha A. Karp Damian Smedley Niels C. Adams Sanger Institute Mouse Genetics Project James N. Bussell David J. Adams Ramiro Ramírez-Solis Karen P. Steel Antonella Galli Jacqueline K. White 《Disease models & mechanisms》2015,8(11):1467-1478