To obtain more knowledge on the origin and genetic diversity of the swamp buffalo (Bubalus bubalis) in China, the complete mitochondrial D-loop sequences of 119 samples representing seven native types were compared. Two mitochondrial DNA (mtDNA) lineages (lineages A and B) were determined for the Chinese swamp buffalo. Examination of the diversity patterns suggest that lineage A has undergone a population expansion event. Divergence of lineages A and B was estimated at 18,000 years ago. Combined analyses of mtDNA sequences from Chinese, Indian, Brazilian/Italian and Southeast Asian/Australian buffalo samples showed independent domestication events in the swamp buffalo from China and the river buffalo from the India subcontinent. The spread of swamp and river buffalo from China and India respectively to mainland Southeast Asia suggests that Southeast Asia is a hybrid zone for buffalo. Our data support the hypothesis of the evolution of domesticated swamp and river buffalo from ancestral swamp-like animals. These ancestral animals were extensively distributed across mainland Asia and most likely are represented today by the wild Asian buffalo (Bubalus arnee).
ABSTRACT. Radiocarbon dating by accelerator mass spectrometry (AMS) of the shell bar section of Qaidam Basin, NE Tibetan Plateau, shows that this section was formed between ~39.7 and ~17.5 14 C kyr BP and represented the highest paleolake development period since the Late Pleistocene. It was difficult to obtain reliable dates due to the low organic carbon content, which was formed mainly by authochtonous algae-bacteria (Zhang et al. 2007a). In order to improve the dating, 14 C ages of both the alkali residual and acid-soluble components of the organic carbon were measured to check the consistency of the dating results. Total organic carbon (TOC) content and stable carbon isotopes (δ 13 C org ) might also be used as critical references for checking the reliability of dates. For example, in our study of the shell bar section from Qaidam Basin, we found that when the TOC content was higher than 0.15% and/or δ 13 C org was lower than -23‰, the AMS dates were reliable. AMS dating of fossil shells demonstrated that they could provide valuable age information. The ages given by fossil shells are comparable to those of bulk carbonate from a similar sampling site, and are about 15~18 kyr older than the ages given by organic matter. Due to the U/Th dating requirements and open nature of the system, we concluded that U/Th dating results are unreliable and that this technique is unsuitable for dating halite deposits from Qaidam Basin.
Field investigations and laboratory analyses show that there existed long-lasting and extensive palaolakes between 18,000 and 42,000 yr B.P. in the Tengger Desert, NW China. This palaolake phase developed in a mild humid-warm climate that was very different from that of present. Geochemical data, palynological evidence and grain size variations demonstrate that the lake levels had fluctuated greatly with the climate changes and these fluctuations can be correlated with the DansgaardOeschger and Heinrich events.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.