Paleogenome Reveals Genetic Contribution of Extinct Giant Panda to Extant Populations.

Historically, the giant panda was widely distributed from northern China to southwestern Asia [1]. As a result of range contraction and fragmentation, extant individuals are currently restricted to fragmented mountain ranges on the eastern margin of the Qinghai-Tibet plateau, where they are distributed among three major population clusters [2]. However, little is known about the genetic consequences of this dramatic range contraction. For example, were regions where giant pandas previously existed occupied by ancestors of present-day populations, or were these regions occupied by genetically distinct populations that are now extinct? If so, is there any contribution of these extinct populations to the genomes of giant pandas living today? To investigate these questions, we sequenced the nuclear genome of an ∼5,000-year-old giant panda from Jiangdongshan, Tengchong County in Yunnan Province, China. We find that this individual represents a genetically distinct population that diverged prior to the diversification of modern giant panda populations. We find evidence of differential admixture with this ancient population among modern individuals originating from different populations as well as within the same population. We also find evidence for directional gene flow, which transferred alleles from the ancient population into the modern giant panda lineages. A variable proportion of the genomes of extant individuals is therefore likely derived from the ancient population represented by our sequenced individual. Although extant giant panda populations retain reasonable genetic diversity, our results suggest that this represents only part of the genetic diversity this species harbored prior to its recent range contractions.

Ancient DNA from Giant Panda (Ailuropoda melanoleuca) of South-Western China Reveals Genetic Diversity Loss during the Holocene.

The giant panda was widely distributed in China and south-eastern Asia during the middle to late Pleistocene, prior to its habitat becoming rapidly reduced in the Holocene. While conservation reserves have been established and population numbers of the giant panda have recently increased, the interpretation of its genetic diversity remains controversial. Previous analyses, surprisingly, have indicated relatively high levels of genetic diversity raising issues concerning the efficiency and usefulness of reintroducing individuals from captive populations. However, due to a lack of DNA data from fossil specimens, it is unknown whether genetic diversity was even higher prior to the most recent population decline. We amplified complete cytb and 12s rRNA, partial 16s rRNA and ND1, and control region sequences from the mitochondrial genomes of two Holocene panda specimens. We estimated genetic diversity and population demography by analyzing the ancient mitochondrial DNA sequences alongside those from modern giant pandas, as well as from other members of the bear family (Ursidae). Phylogenetic analyses show that one of the ancient haplotypes is sister to all sampled modern pandas and the second ancient individual is nested among the modern haplotypes, suggesting that genetic diversity may indeed have been higher earlier during the Holocene. Bayesian skyline plot analysis supports this view and indicates a slight decline in female effective population size starting around 6000 years B.P., followed by a recovery around 2000 years ago. Therefore, while the genetic diversity of the giant panda has been affected by recent habitat contraction, it still harbors substantial genetic diversity. Moreover, while its still low population numbers require continued conservation efforts, there seem to be no immediate threats from the perspective of genetic evolutionary potential.

[Determination of zinc in relish by derivate flame atomic absorption spectrometry with microsampling pulse nebulization].

A simple, rapid, microsampling method for the determination of zinc in relish by derivative FAAS is described. The influences of microsampling volume and other factors are discussed. The detection limit and sensitivity of the proposed method are 0.013 and 0.004 microg x mL(-1), respectively. The samples were centrifugalized and diluled with 1.5% HCl solution, and then analysized directly. The method was applied to the determination of zinc in relish with a recovery of 93.3%-113.3% and relative standard deviation of 3.0%-4.4%.

[Determination of copper, iron and zinc in tapwater by ion exchange microcolumn preconcentration-derivative flame atomic absorption spectrometry].

A new microsample-pulse method is described for the determination of copper, iron and zinc by ion exchange microcolumn preconcentration-derivative flame atomic absorption spectrometry. The optimum conditions concerning the sensitivity were studied. The method was applied to the determination of Cu, Fe and Zn in tapwater with sensitivity being 0.29, 0.59 and 0.06 microgram.L-1, respectively. The recovery range and the relative standard deviation of the proposed method were 91.13%-101.34% and 1.95%-4.28%, respectively. The detection limits were found to be 1.28, 5.85 and 0.68 micrograms.L-1, respectively. The method is sensitive, accurate, precise and rapid.