Prion protein gene (PRNP) polymorphisms in native Chinese cattle

Le polymorphisme au sein de quatre regions du gene codant pour la proteine prion bovine (PRNP) confere la susceptibilite a l'encephalopathie bovine spongiforme (BSE). Ceux-ci comprennent un polymorphisme d'insertion/deletion (indel) de 23 pb dans le promoteur, un indel de 12 pb dans l'intron 1, un octapeptide repete ou un indel de 24 pb au sein du cadre de lecture, et un polymorphisme mononucleotidique (SNP) dans la region codante. Dans ce travail, les auteurs ont examine la frequence des genotypes, des alleles et des haplotypes pour ces indel au sein de 349 bovins d'origine chinoise, de meme que la sequence nucleotidique de ce gene chez 50 de ces animaux. Leurs resultats montrent que l'allele ayant la deletion de 12 pb et l'haplotype combinant la deletion de 23 pb et la deletion de 12 pb, lesquels ont ete suggeres comme etant importants pour la susceptibilite a la BSE, sont rares au sein des bovins du sud de la Chine. Une difference significative a ete observee entre les bovins affectes par la BSE et les bovins chinois sains pour ce qui est de l'indel de 12 pb. Au total, 14 SNP ont ete observes dans la region codante du gene PRNP chez les bovins chinois. Trois de ces SNP etaient associes a des changements d'acides amines (K3T, P54S et S154N). La substitution E211K qui a ete rapportee recemment chez un cas atypique de la BSE chez un bovin americain n'a pas ete detectee dans ce travail.

Duplication and functional diversification of pancreatic ribonuclease (RNASE1) gene

Adaptation is one of the most fundamental issues in the studies of organismal evolution. Pancreatic ribonuclease is a very important digestive enzyme and secreted by the pancreas. Numerous studies have suggested that RNASE1 gene duplication is closely related to the functional adaptation of the digestive system in the intestinal fermentation herbivores. RNASE1 gene thus becomes one of the most important candidate genetic markers to study the molecular mechanism of adaptation of organisms to the feeding habit. Interestingly, RNASE1 gene duplication has also been found in some non-intestinal fermentation mammals, suggesting that RNASE1 gene may have produced novel tissue specificity or functions in these species. In this review, RNASE1 gene and its implications in adaptive evolution, especially in association with the feeding habit of organisms, are summarized.

Parallel and Convergent Evolution of the Dim-Light Vision Gene RH1 in Bats (Order: Chiroptera)

Rhodopsin, encoded by the gene Rhodopsin (RH1), is extremely sensitive to light, and is responsible for dim-light vision. Bats are nocturnal mammals that inhabit poor light environments. Megabats (Old-World fruit bats) generally have well-developed eyes, while microbats (insectivorous bats) have developed echolocation and in general their eyes were degraded, however, dramatic differences in the eyes, and their reliance on vision, exist in this group. In this study, we examined the rod opsin gene (RH1), and compared its evolution to that of two cone opsin genes (SWS1 and M/LWS). While phylogenetic reconstruction with the cone opsin genes SWS1 and M/LWS generated a species tree in accord with expectations, the RH1 gene tree united Pteropodidae (Old-World fruit bats) and Yangochiroptera, with very high bootstrap values, suggesting the possibility of convergent evolution. The hypothesis of convergent evolution was further supported when nonsynonymous sites or amino acid sequences were used to construct phylogenies. Reconstructed RH1 sequences at internal nodes of the bat species phylogeny showed that: (1) Old-World fruit bats share an amino acid change (S270G) with the tomb bat; (2) Miniopterus share two amino acid changes (V104I, M183L) with Rhinolophoidea; (3) the amino acid replacement I123V occurred independently on four branches, and the replacements L99M, L266V and I286V occurred each on two branches. The multiple parallel amino acid replacements that occurred in the evolution of bat RH1 suggest the possibility of multiple convergences of their ecological specialization (i.e., various photic environments) during adaptation for the nocturnal lifestyle, and suggest that further attention is needed on the study of the ecology and behavior of bats.

Tracing the Origins of Hakka and Chaoshanese by Mitochondrial DNA Analysis

Hakka and Chaoshanese are two unique Han populations residing in southern China but with northern Han (NH) cultural traditions and linguistic influences. Although most of historical records indicate that both populations migrated from northern China in the last two thousand years, no consensus on their origins has been reached so far. To shed more light on the origins of Hakka and Chaoshanese, mitochondrial DNAs (mtDNAs) of 170 Hakka from Meizhou and 102 Chaoshanese from Chaoshan area, Guangdong Province, were analyzed. Our results show that some southern Chinese predominant haplogroups, e.g. B, F, and M7, have relatively high frequencies in both populations. Although median network analyses show that Hakka/Chaoshanese share some haplotypes with NH, interpopulation comparison reveals that both populations show closer affinity with southern Han (SH) populations than with NH. In consideration of previous results from nuclear gene (including Y chromosome) research, it is likely that matrilineal landscapes of both Hakka and Chaoshanese have largely been shaped by the local people during their migration southward and/or later colonization in southern China, and factors such as cultural assimilation, patrilocality, and even sex-bias in the immigrants might have played important roles during the process. Am J Phys Anthropol 141:124-130, 2010. (C) 2009 Wiley-Liss, Inc.

Updating the East Asian mtDNA phylogeny: a prerequisite for the identification of pathogenic mutations

Knowledge about the world phylogeny of human mitochondrial DNA (mtDNA) is essential not only for evaluating the pathogenic role of specific mtDNA mutations but also for performing reliable association studies between mtDNA haplogroups and complex disorder

Reply to van Oven: Suggestions and caveats for naming mtDNA haplogroup

The authors thank all subjects for their participation and Mr. Wen-Zhi Wang for helpful assistance with the data analysis. This study was supported in part by grants (30725044) from the National Natural Science Foundation of China.

Ribosomal DNA gene and phylogenetic relationships of Diplura and lower Hexapods

The monophyly of Diplura and its phylogenetic relationship with other hexapods are important for understanding the phylogeny of Hexapoda. The complete 18SrRNA gene and partial 28SrRNA gene (D3-D5 region) from 2 dipluran species (Campodeidae and Japygidae), 2 proturan species, 3 collembolan species, and 1 locust species were sequenced. Combining related sequences in GenBank, phylogenetic trees of Hexapoda were constructed by MP method using a crustacean Artemia salina as an outgroup. The results indicated that: (i) the integrated data of 18SrDNA and 28SrDNA could provide better phylogenetic information, which well supported the monophyly of Diplura; (ii) Diplura had a close phylogenetic relationship to Protura with high bootstrap support.