Analysis on Genetic Diversity and Isolation Mechanism by Distance of Different Ecological Type Sheep Breeds in Mon-golia Sheep Group

In the present study with Tan sheep, small-tailed Han sheep, Hu sheep, Tong sheep, and Wadi sheep, we detected the distribution of gene frequency of several microsatellite sites in different chromosomes, the result showed that： 1） Hu sheep was in the status of Hardy-Weinberg extreme disequilibrium （P 〈 0.01）, while populations including Tong sheep, small-tailed Han sheep, Tan sheep, and Wadi sheep were in Hardy-Weinberg equilibrium （P 〉 0.05）. 2） Variance analysis of the heterozygosity and poly- morphic information content at rnicrosatellite makers showed that there were not significant differences among populations as to heterozygosity and PIC （P 〉 0.05）, as to effective number of alleles there were not significant differences both among Tan sheep, Hu sheep, Tong sheep, and Wadi sheep, and between Wadi sheep and small-tailed sheep （P 〉 0.05）, but between the former three populations and the latter two populations, there were significant differences （0.01〈 P 〈0.05）. The variation levels of small-tailed Han sheep was the highest in the five populations based on microsatellite maker data, subsequently followed by Wadi sheep, Tong sheep, Tan sheep, and then Hu sheep. 3） The phylogenetic relationships of the five sheep populations in this study did not meet the mechanism of isolation by distance, and the genetic differentiation relationships among five sheep populations were not closely linearly correlative with their geography distribution. Our findings supported related records in literature： The five populations originated on different time stage from the primogenitor population and communicated genetically with each other thereafter in the process of natural and artificial selection and on different ecological environment.

论葫芦岛大青山建立国家级自然保护区的必要性

葫芦岛大青山县级自然保护区是辽西地区森林生态类型的典型代表,地理位置独特,地处我国"三北"生态敏感带上,区内充分体现生态类型的多样性和生物物种的多样性,建立大青山国家级保护区对于加大保护力度、抢救自然物种、修复生态、保障地区生态功能具有重要意义。

Seed Protein Electrophoresis for Assessment of Genetic Diversity among Festuca pratensis Huds, Local Ecotypes

Fifty two accessions of Festuca pratensis Huds. were analysed of which 18 had been collected in Switzerland and 32 in Bulgaria. SDS-PAGE of seed proteins was implemented to detect genetic variation among ecotype populations using a modification of UPOV method for barley. The modification concerns mainly protein extracting procedure as detailed described in the protocol. The two cultivars Preval and Cosmolit were used as standards. Cluster analyses and correspondence analyses/scatter plot were used as statistic approaches for determining genetic diversity among individual ecotypes and groups of ecotypes. Electrophoretic spectra of proteins show clear differences among local accessions in relation to their origin. In Swiss ecotypes 32 protein fragments were determined whereas in Bulgarian local populations their number was 68. Each of the two eco-groups possesses fragments that appear in all accessions of the group. The number of monomorphic bands within Bulgarian local ecotypes is four whereas their number in Swiss ecotypes is 12. Four monomorphic bands appearing in all proteinograms no difference of eco-groups was identified with Rm values of： 0.43, 0.55, 0.58, 0.82. A higher level of protein band polymorphism was proven in Bulgarian ecotypes in comparison with Swiss ecotypes. Thirty seven polymorphic bands occurred exclusively in the Bulgarian local ecotypes and had a frequency of 0.03 or higher whereas within Swiss ecotypes was detected one unique protein fragment. SDS-PAGE ＂fingerprinting＂ is suggested as a fast and easy approach to differentiate F. pratensis ecotypes by their origin as well for detection of foreign germplasm for inclusion in breeding programs.

A generalized model of island biogeography

MacArthur and Wilson's equilibrium theory is one of the most influential theories in ecology.Although evolution on islands is to be important to island biodiversity,speciation has not been well integrated into island biogeography models.By incorporating speciation and factors influencing it into the MacArthur-Wilson model,we propose a generalized model unifying ecological and evolutionary processes and island features.Intra-island speciation may play an important role in both island species richness and endemism,and the contribution of speciation to local species diversity may eventually be greater than that of immigration under certain conditions.Those conditions are related to the per species speciation rate,per species extinction rate,and island features,and they are independent of immigration rate.The model predicts that large islands will have a high,though not the highest,proportional endemism when other parameters are fixed.Based on the generalized model,changes in species richness and endemism on an oceanic island over time were predicted to be similar to empirical observations.Our model provides an ideal starting point for re-evaluating the role of speciation and re-analyzing available data on island species diversity,especially those biased by the MacArthur-Wilson model.