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Ya-ping Zhang

Publications and source records attributed to Ya-ping Zhang.

23 records · Page 2Linked to original sources
PubMed2002

Genetic evidence for an East Asian origin of domestic dogs.

The origin of the domestic dog from wolves has been established, but the number of founding events, as well as where and when these occurred, is not known. To address these questions, we examined the mitochondrial DNA (mtDNA) sequence variation among 654 domestic dogs representing all major dog populations worldwide. Although our data indicate several maternal origins from wolf, >95% of all sequences belonged to three phylogenetic groups universally represented at similar frequencies, suggesting a common origin from a single gene pool for all dog populations. A larger genetic variation in East Asia than in other regions and the pattern of phylogeographic variation suggest an East Asian origin for the domestic dog, approximately 15,000 years ago.

Animals↗
PubMed2002

Adaptive evolution of a duplicated pancreatic ribonuclease gene in a leaf-eating monkey.

Although the complete genome sequences of over 50 representative species have revealed the many duplicated genes in all three domains of life, the roles of gene duplication in organismal adaptation and biodiversity are poorly understood. In addition, the evolutionary forces behind the functional divergence of duplicated genes are often unknown, leading to disagreement on the relative importance of positive Darwinian selection versus relaxation of functional constraints in this process. The methodology of earlier studies relied largely on DNA sequence analysis but lacked functional assays of duplicated genes, frequently generating contentious results. Here we use both computational and experimental approaches to address these questions in a study of the pancreatic ribonuclease gene (RNASE1) and its duplicate gene (RNASE1B) in a leaf-eating colobine monkey, douc langur. We show that RNASE1B has evolved rapidly under positive selection for enhanced ribonucleolytic activity in an altered microenvironment, a response to increased demands for the enzyme for digesting bacterial RNA. At the same time, the ability to degrade double-stranded RNA, a non-digestive activity characteristic of primate RNASE1, has been lost in RNASE1B, indicating functional specialization and relaxation of purifying selection. Our findings demonstrate the contribution of gene duplication to organismal adaptation and show the power of combining sequence analysis and functional assays in delineating the molecular basis of adaptive evolution.

Amino Acid Sequence↗
PubMed2002

[Research on the identification of penis et testis cervi with molecular taxonomy].

OBJECTIVE: To make the kit with witch to identify Penis et Testis Cervi with molecular taxonomy. METHOD: The mtDNA of sika and red deer from different areas was amplified by PCR and sequenced. Compared with the mtDNA of bovine and horse from witch the false medicines were made, characteristic segments of deer were found. We selected one as the species distinctive PCR primer of deer. RESULT: The kit made up with this primer and related reagents could be used to discern Penis et Testis Cervi from the false medicine. CONCLUSION: It is a scientific, steady, accurate and convenient way to identify Penis et Testis Cervi with molecular taxonomy.

Animals↗
PubMed2002

[Genotype, melanocortin 1 receptor and ultraviolet radiation].

Recent work on the melanocortin 1 receptor (MC1R) suggests that MC1R plays a central role in regulation of eumelanin (brown/black melanins) and phaeomelanin (red/yellow melanins) synthesis within the mammalian melanocyte. In the mouse,genetic studies show that the MC1R appears to be a unique, bifunctionally controlled receptor, activated by alpha-MSH and antagonized by agouti,both of which contribute to the variability seen in mammalian coat color. Variants of this receptor are associated with different animal's coat,human skin and hair colors. In addition, cutaneous pigmentation is a major determinant of the cutaneous response to ultraviolet radiation,and consequently of the risk of developing skin cancer. MC1R variants are a risk factor for melanoma susceptibility.

English Abstract↗