排序方式: 共有74条查询结果,搜索用时 15 毫秒
1.
mtDNA diversity in rhesus monkeys reveals overestimates of divergence time and paraphyly with neighboring species 总被引:4,自引:0,他引:4
Reconstructions of the human-African great ape phylogeny by using
mitochondrial DNA (mtDNA) have been subject to considerable debate. One
confounding factor may be the lack of data on intraspecific variation. To
test this hypothesis, we examined the effect of intraspecific mtDNA
diversity on the phylogenetic reconstruction of another Plio- Pleistocene
radiation of higher primates, the fascicularis group of macaque (Macaca)
monkey species. Fifteen endonucleases were used to identify 10 haplotypes
of 40-47 restriction sites in M. mulatta, which were compared with similar
data for the other members of this species group. Interpopulational,
intraspecific mtDNA diversity was large (0.5%- 4.5%), and estimates of
divergence time and branching order incorporating this variation were
substantially different from those based on single representatives of each
species. We conclude that intraspecific mtDNA diversity is substantial in
at least some primate species. Consequently, without prior information on
the extent of genetic diversity within a particular species, intraspecific
variation must be assessed and accounted for when reconstructing primate
phylogenies. Further, we question the reliability of hominoid mtDNA
phylogenies, based as they are on one or a few representatives of each
species, in an already depauperate superfamily of primates.
相似文献
2.
Monsalve MV Helgason A Devine DV 《Proceedings. Biological sciences / The Royal Society》1999,266(1434):2209-2216
A number of studies based on linguistic, dental and genetic data have proposed that the colonization of the New World took place in three separate waves of migration from North-East Asia. Recently, other studies have suggested that only one major migration occurred. It is the aim of this study to assess these opposing migration hypotheses using molecular-typed HLA class II alleles to compare the relationships between linguistic and genetic data in contemporary Native American populations. Our results suggest that gene flow and genetic drift have been important factors in shaping the genetic landscape of Native American populations. We report significant correlations between genetic and geographical distances in Native American and East Asian populations. In contrast, a less clear-cut relationship seems to exist between genetic distances and linguistic affiliation. In particular, the close genetic relationship of the neighbouring Na-Dene Athabaskans and Amerindian Salishans suggests that geography is the more important factor. Overall, our results are most congruent with the single migration model. 相似文献
3.
Mattevi VS Fiegenbaum M Salzano FM Weiss KM Moore J Monsalve MV Devine DV Hutz MH 《American journal of physical anthropology》2000,112(3):311-317
Haplotypes derived from five polymorphic restriction sites were determined in 50 Carrier-Sekani and 70 Mvskoke chromosomes, and the results were integrated with those previously obtained for 11 South American Indian populations. Eleven haplotypes were identified in the Mvskokes, while five were observed in the Carrier-Sekani. As in South American natives, haplotype 2 (+----) and 6 (-++ -+) were the most prevalent among the Mvskoke (46% and 30%, respectively). In the Carrier-Sekani, haplotype 2 was also the most common, but haplotype 5 (-+ -++) was somewhat more frequent (18%) than 6 (12%). High heterozygosities, as well as genetic differentiation, were observed among these two North American and two other South American groups (Mapuche and Xavante). They could be due to non-Indian admixture in the Mvskoke and Mapuche, but the findings in the other two populations require some other type of explanation. 相似文献
4.
Marcella Salzano Marta Sanz-García Diana M Monsalve David S Moura Pedro A Lazo 《Epigenetics》2015,10(5):373-383
All types of DNA damage cause a local alteration and relaxation of chromatin structure. Sensing and reacting to this initial chromatin alteration is a necessary trigger for any type of DNA damage response (DDR). In this context, chromatin kinases are likely candidates to participate in detection and reaction to a locally altered chromatin as a consequence of DNA damage and, thus, initiate the appropriate cellular response. In this work, we demonstrate that VRK1 is a nucleosomal chromatin kinase and that its depletion causes loss of histones H3 and H4 acetylation, which are required for chromatin relaxation, both in basal conditions and after DNA damage, independently of ATM. Moreover, VRK1 directly and stably interacts with histones H2AX and H3 in basal conditions. In response to DNA damage induced by ionizing radiation, histone H2AX is phosphorylated in Ser139 by VRK1. The phosphorylation of H2AX and the formation of γH2AX foci induced by ionizing radiation (IR), are prevented by VRK1 depletion and are rescued by kinase-active, but not kinase-dead, VRK1. In conclusion, we found that VRK1 is a novel chromatin component that reacts to its alterations and participates very early in DDR, functioning by itself or in cooperation with ATM. 相似文献
5.
6.
Oscar Palomares Rafael I Monsalve Rosalía Rodríguez Mayte Villalba 《European journal of biochemistry》2002,269(10):2538-2545
2S albumin storage proteins from rapeseed (Brassica napus), called napins, consist of two different polypeptide chains linked by disulphide bridges, which are derived by proteolytic cleavage from a single precursor. The precursor form of the napin BnIb (proBnIb) has been cloned using a PCR strategy and sequenced. The amino-acid sequence deduced from the clone includes 31 residues of the small chain and 75 of the large chain, which are connected by the peptide Ser-Glu-Asn. Expression of the cDNA encoding proBnIb has been carried out in the methylotrophic yeast Pichia pastoris. The induced protein was secreted to the extracellular medium at a yield of 80 mg.L(-1) of culture and was purified by means of size-exclusion chromatography and reverse phase-HPLC. Recombinant proBnIb appeared properly folded as its molecular and spectroscopic properties were equivalent to those of the mature heterodimeric protein. As 2S albumin storage proteins from Brassicaceae have been shown to be type I allergy inducers, the immunological activity of the recombinant proBnIb was analysed as a measure of its structural integrity. The immunological properties of the recombinant precursor and the natural napin were indistinguishable by immunoblotting and ELISA inhibition using polyclonal antisera and sera of patients allergic to mustard and rapeseed. In conclusion, the recombinant expression of napin precursors in P. pastoris has been shown to be a successful method for high yield production of homogeneous and properly folded proteins whose polymorphism and complex maturation process limited hitherto their availability. 相似文献
7.
Antigen 5 is a major allergen of vespid venom. It has partial sequence identity with proteins from diverse sources. The biologic function of Ag 5 and its related proteins is not known. We are interested in the expression of Ag 5 with the native conformation of the natural protein since its B cell epitopes are mainly of the discontinuous type. When expressed in bacteria, recombinant Ag 5 formed an insoluble intracellular product, and it did not translocate from cytoplasm to periplasm by the addition of a pelB leader sequence to the cloned protein. When expressed in yeast Pichia pastoris, Ag 5 was secreted because the cloned protein contained a yeast alpha signal leader sequence. Recombinant Ag 5 from yeast was shown to have the native structure of the natural protein and the recombinant Ag 5 from bacteria did not. This was shown by comparison of their solubility, electrophoretic behavior, disulfide bond content, CD spectrum, and binding of IgE antibodies from allergic patients and IgG antibodies from mice immunized with natural Ag 5 or recombinant Ag 5s from yeast or bacteria. These studies were made with Ag 5s from yellowjacket (Vespula vulgaris) and paper wasp (Polistes annularis). 相似文献
8.
9.
Sánchez-Solana B Nueda ML Ruvira MD Ruiz-Hidalgo MJ Monsalve EM Rivero S García-Ramírez JJ Díaz-Guerra MJ Baladrón V Laborda J 《Biochimica et biophysica acta》2011,1813(6):1153-1164
The protein DLK2, highly homologous to DLK1, belongs to the EGF-like family of membrane proteins, which includes NOTCH receptors and their DSL-ligands. The molecular mechanisms by which DLK proteins regulate cell differentiation and proliferation processes are not fully established yet. In previous reports, we demonstrated that DLK1 interacts with itself and with specific EGF-like repeats of the NOTCH1 extracellular region involved in the binding to NOTCH1 canonical ligands. Moreover, the interaction of DLK1 with NOTCH1 caused an inhibition of basal NOTCH signaling in preadipocytes and mesenchymal multipotent cells. In this work, we demonstrate, for the first time, that DLK2 interacts with itself, with DLK1, and with the same NOTCH1 receptor region as DLK1 does. We demonstrate also that the interaction of DLK2 with NOTCH1 similarly results in an inhibition of NOTCH signaling in preadipocytes and Mouse Embryo fibloblasts. In addition, we demonstrate that a membrane DLK1 variant, lacking the sequence recognized by the protease TACE, also inhibits NOTCH signaling. Furthermore, both DLK1 and DLK2 are able to decrease NOTCH activity also when triggered by specific NOTCH ligands. However, the decrease in NOTCH signaling induced by overexpression of Dlk2 is reversed by the overexpression of Dlk1, and viceversa. We conclude that DLK1 and DLK2 act as inhibitory non-canonical protein ligands for the NOTCH1 receptor that modulate NOTCH signaling. 相似文献