Microsatellite analysis of genetic diversity and population structure of Chinese mitten crab (Eriocheir sinensis)

Chinese mitten crab （Eriocheir sinensis） has higher commercial value as food source than any other species of Eriocheir in China. To evaluate the germplasm resources and characterize the genetic diversity and population structure of the crabs in different water systems, two stocks and two farming populations were assessed with 25 polymorphic microsallite loci available in public GenBank. Basic statistics showed that the average observed heterozygosity （Ho） amongst populations ranged from 0.5789 to 0.6824. However, a remarkable presence of inbreeding and heterozygote deficiencies were observed. To analyze population structure, pairwise FST coefficients explained only -10.3% variability from the subdivision of mitten crab populations, the remaining variability stems from the subdivision within subpopulations. Although the four populations had slight differentiation, different allelic frequencies resulted in distinct population structures. Two stocks and one farming population were clustered together to the phylogenetic branch of Yangtze crab, with an approximate membership of 95%. Whereas, another farming population was clustered singly to the phylogenetic branch of the Liaohe crab, with a membership of 97.1%. The tests for individual admixture showed that Yangtze crab had probably been contaminated with individuals from other water systems. Genetic relationships between populations also supported the conclusion that Yangtze crab and Liaohe crab had different gene pools in spite of the origins of the same species.

Germplasm of breeding Pseudosciaena crocea as revealed by microsatellite markers

The germplasm of breeding large yellow croaker （Pseudosciaena crocea Richardson） was revealed using 12 microsatellite markers. The results showed that the genetic diversities were on a mediated level in the bred Daiqu and Min - Yue stocks and two hybrid groups, as represented by 4.83 of the mean number of alleles and 0.561 of the average observed heterozygosity. The value of pair- wise differentiation coefficient（ FST ） was only 13. 1% between Daiqu and Min -Yue stocks, demonstrating the low level of differentiation and a close relationship. However, STRUCTURE simulations and phylogenetic tree based on the UPGMA method supported that they are geographically different populations of the same species with distinct genetic structures. Examinations of individual admixture showed that Min - Yue stock had been contaminated by alien individuals. Moreover, the genetic structures of the two hybrid groups resembled those of their parents, especially affected more by their female parents. Finally, the values of average observed heterozygosity between parents and their ascendants were compared and tested, as a result of no detectable differences （P 〉 0. 05）.

Preparation of Fe3O4-porphyrin Nano-composited Particles and Their Optical and Magnetic Properties

Magnetic Fe3O4 nanoparticles were synthesized via the coprecipitation of ferrous and ferric ion. The morphology and magnetic properties of the magnetic Fe3O4 nanoparticles were investigated by transmission electron microscopy（TEM） and superconducting quantum interference device. Furthermore, the Fe3O4-porphyrin nanocompo- site particles（FeOPNCPs） are prepared with Fe3O4 and porphyrin by sol-gel method. The patterns of FeOPNCPs were also characterized by means of scanning electron microscopy（SEM） and TEM. The optical and magnetic properties of FeOPNCPs were investigated on a UV-Vis spectrophotometer, a fluorescence spectrophotometer and a supercon- ducting quantum interference device. These experimental results show that FeOPNCPs not only possess optical features of porphvrin but also retain the superoaramagnetic features of Fe3O4 nanoparticles.