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.

Gynogenesis and sex determination in large-scale loach Paramisgurnus dabryanus (Sauvage)

Gynogenesis was induced using heterologous sperms in large-scale loach, Paramisgurnus dabryanus (Sauvage), in which a ZW/ZZ sex determination was previously proposed. Three microsatellite loci were used to monitor exclusive maternal inheritance of gynogenetic progenies. The results showed that high percentages of meiogynogens were produced at 4 min post-fertilization and mitogynogens were produced at 18 min post-fertilization by heat shocks, while meiotic gynogenesis was induced by cold shocks within a wide period and high heterozygosity was even observed in gynogens produced at 24 min post-fertilization. The sex ratios of the F, progenies in three gynogenetic families were significantly deviated from 1: 1 expectation with a female bias in two families and a male bias in one family (P < 0.05), and the other four gynogenetic families showed approximate 1:1 sex ratios. Moreover, the self-mating between gynogenetic F, progenies and mating between gynogenetic F, progenies and normal individuals produced all-female progenies or identical proportions of females and males. The data of sex ratios generally confirmed that the sex determination in large-scale loach was determined by the putative ZW/ZZ system, and the possible reasons causing the biased sex ratios are discussed.

Social and ecological influences on dispersal and philopatry in the plateau pika (Ochotona curzoniae)

Benefits and costs of dispersal and philopatry of the social plateau pika (Ochotona curzoniae) were studied on the Tibetan plateau for 3 years. Although short-lived, plateau pikas live in cohesive family groups that occupy burrow systems in sedge meadow habitat Most (57.8%) plateau pikas were philopatric, and dispersal movements were extremely restricted. No juvenile females or adult pikas moved more than two family ranges between years; the greatest observed dispersal distances were by two juvenile males that moved five family ranges from the family of their birth. Traversing unfamiliar habitat was not a cost of pika dispersal because most dispersers settled in families that they could easily visit before dispersal. Dispersal movements appeared to result in equalization of density among pika families, an expected result if competition for environmental resources influenced dispersal. Males did not disperse to gain advantages in competition for mates, as evidenced by their moving to families with significantly fewer females. Females, however, moved to families with significantly more males. Males provide abundant paternal care, and significantly more offspring per female survived to become adults from families with more adult males per adult female. Evidence concerning the influence of inbreeding avoidance on natal dispersal was indirect. Some males exhibited natal philopatry; thus some families had opportunity for close inbreeding. Males and females that dispersed had no opposite-sex relatives in their new families. Philopatric pikas may have benefited by remaining in families that exhibited low local densities, and philopatric females might have benefited from social cooperation with relatives.

Effects of superimposed pulse bias on TiN coating in cathodic arc deposition

Orthogonal designs are used to investigate the main factors when doing experiments in which pulse bias is superimposed on d.c. bias during cathodic are deposition of TiN. Pulse peak, duty cycle, frequency, direct voltage, are current and pressure all are investigated when coating TiN on HSS substrates. Roughness, surface micrograph, microhardness and thickness are tested. By analysis of variance, it is shown that pressure and frequency are the main factors. R-a and droplet density of the film with (d.c. + pulse) bias decrease. A simple explanation for the result is suggested.

Guiding neutral atoms with two current-carrying wires and a vertical bias field on the atom chip

We demonstrate the guiding of neutral atoms with two parallel microfabricated current-carrying wires on the atom chip and a vertical magnetic bias field. The atoms are guided along a magnetic field minimum parallel to the current-carrying wires and confined in the other two directions. We describe in detail how the precooled atoms are efficiently loaded into the two-wire guide. We present a detailed experimental study of the motional properties of the atoms in the guide and the relationship between the location of the guide and the vertical bias field. This two-wire guide with vertical bias field can be used to realize large area atom interferometer.

High-density comparative BAC mapping in the black muntjac (Muntiacus crinifrons): Molecular cytogenetic dissection of the origin of MCR 1p+4 in the X1X2Y1Y2Y3 sex chromosome system

The black muntjac (Muntiacus crinifrons, 2n = 8 female/9 male) is a critically endangered mammalian species that is confined to a narrow region of southeastern China. Male black muntjacs have an astonishing X1X2Y1Y2Y3 sex chromosome system, unparalleled i

Analyses of genetic structure of Tibeto-Burman populations reveals sex-biased admixture in southern Tibeto-Burmans

An unequal contribution of male and female lineages from parental populations to admixed ones is not uncommon in the American continents, as a consequence of directional gene flow from European men into African and Hispanic Americans in the past several c