高血压病、冠心病、糖尿病、癌症的遗传因素

近来陆续收到一些读者来信,询问高血压病、冠心病、糖尿病、癌症等疾病的遗传问题,故撰写此文,以飨读者。 高血压病 高血压病亦称原发性高血压,其病因除了与神经精神因素、饮食不当等因素有关外,亦与遗传有一定关系。 高血压病的确切遗传方式目前还不太清楚,但是一点可以肯定。

Studies on the Inheritance of Locule Formation in Tomatoes (Lycopersicon esculentum Mill.)

To fully understand the tomato ovary locule formation of inheritance, two varieties, ovary multi-locule （MLK1） and few-locule （FL1）, were used in these studies. Using reciprocal cross, self-cross, and backcross, we have constructed various groups to seek the genetic law and mechanisms of tomato locule formation, for modifying the tomato breeding theory. The parental and the resulting FI and F2 generations have been used to examine the heredity of the locule number. The results showed that few-locule was incompletely dominant. The data from backcross demonstrated a significant effect on the locule number, whereas, the reciprocal cross showed an insignificant effect. Not surprisingly, the locule number was controlled by nuclear genomes, not by exogenous substances. The model that inherited the locule number belonged to the additive-dominant model： additive effects played a very important role and were partially dominant. In addition, the results revealed that the locule number in tomato was mainly controlled by a single gene, whereas, it was modulated by a number of other genes. Finally, the general inheritability and narrow inheritability of the locule number were 69.44% and 52.98%, respectively.

3D graphical visualization of the genetic architectures underlying complex traits in multiple environments

An approach for generating interactive 3D graphical visualization of the genetic architectures of complex traits in multiple environments is described. 3D graphical visualization is utilized for making improvements on traditional plots in quan- titative trait locus (QTL) mapping analysis. Interactive 3D graphical visualization for abstract expression of QTL, epistasis and their environmental interactions for experimental populations was developed in framework of user-friendly software QTLNetwork (http://ibi.zju.edu.cn/software/qtlnetwork). Novel definition of graphical meta system and computation of virtual coordinates are used to achieve explicit but meaningful visualization. Interactive 3D graphical visualization for QTL analysis provides geneticists and breeders a powerful and easy-to-use tool to analyze and publish their research results.

Development of Three Multiplex PCR Primer Sets for Ark Shell(Scapharca broughtonii)and Their Validation in Parentage Assignment

Scapharca broughtonii is a commercially important and over-exploited species.In order to investigate its genetic diversity and population structure,43 novel polymorphic microsatellites were isolated and characterized.The number of alleles per locus ranged from 3 to 22 with an average of 6.93,and the observed and expected heterozygosities varied between 0.233 and 1.000,and 0.250 and 0.953,with an average of 0.614 and 0.707,respectively.Three highly informative multiplex PCRs were developed from nine of those microsatellites for S.broughtonii.We evaluated and validated these multiplex PCRs in 8 full-sib families.The average polymorphism information content(PIC) was 0.539.The frequency of null alleles was estimated as 3.13% of all the alleles segregation based on a within-family analysis of Mendelian segregation patterns.Parentage analysis of real offspring demonstrated that 100% of all offspring were unambiguously allocated to a pair of parents based on 3 multiplex sets.Those 43 microsatellite loci with high variability will be helpful for the analysis of population genetics and conservation of wild stock of S.broughtonii.The 3 sets of multiplex PCRs could be an important tool of pedigree reconstruction,population genetic analysis and brood stock management.

Microsatellite analysis of variation among wild, domesticated, and genetically improved populations of blunt snout bream （Megalobrama amblycephala）

In the present study, the genetic diversity of one selected strain （Pujiang No. 1）, two domesticated populations （GA and HX） and four wild populations （LZ, YN, SS and JL） of blunt snout bream （Megalobrama amblycephala） was analyzed using 17 microsatellite markers. The results showed that an average of 4.88-7.65 number of alleles （A）; an average of 3.20-5.33 effective alleles （Ne）; average observed beterozygosity （Ho） of 0.6985-0.9044; average expected beterozygosity （He） of 0.6501--0.7805; and the average polymorphism information content （PIC） at 0.5706-0.7226. Pairwise FST value between populations ranged from 0.0307-0.1451, and Nei＇s standard genetic distance between populations was 0.0938-0.4524. The expected heterozygosities in the domesticated populations （GA and HX） were significantly lower than those found in three wild populations （LZ, SS and JL）, but no difference was detected when compared with the wild YN population. Likewise, no difference was found between the four wild populations or two domesticated populations. The expected heterozygosity in Pujiang No. 1 was higher than the two domesticated populations and lower than the four wild populations. Regarding pairwise Fsr value between populations, permutation test P-values were significant between the GA, HX and PJ populations, but not between the four wild populations. These results showed that the expected beterozygosity in the selected strain of blunt snout bream, after seven generations of selective breeding, was lower than that of wild populations, but this strain retains higher levels of genetic diversity than domesticated populations. The genetic differences and differentiation amongst wild populations, domesticated populations and the genetically improved strain of blunt snout bream will provide important conservation criteria and guide the utilization of germplasm resources.

Bioinformatic Tools for Polyploid Crops

Polyploidy is common among agriculturally important crops. Popular genetic methods and their implementations cannot always be applied to polyploid genetic data. We give an overview about available tools and their limitations in terms of levels of ploidy, auto- and allo-ploidy. The main classes of tools are genotype calling, linkage mapping and haplotyping. The usability of the tools is discussed with a focus on their applicability to data sets produced by state of the art technologies. We show that many challenges remain until the toolset for polyploidy provides similar functionalities as those which are already available for diploids. Some tools have been developed over a decade ago and are now outdated. In addition, we discuss necessary steps to overcome this shortage in the future.

Methods Comparison for Microsatellite Marker Development:Different Isolation Methods,Different Yield Efficiency

Microsatellite markers have become one kind of the most important molecular tools used in various researches. A large number of microsatellite markers are required for the whole genome survey in the fields of molecular ecology,quantitative genetics and genomics. Therefore,it is extremely necessary to select several versatile,low-cost,efficient and time-and labor-saving methods to develop a large panel of microsatellite markers. In this study,we used Zhikong scallop(Chlamys farreri) as the target species to compare the efficiency of the five methods derived from three strategies for microsatellite marker development. The results showed that the strategy of constructing small insert genomic DNA library resulted in poor efficiency,while the microsatellite-enriched strategy highly improved the isolation efficiency. Although the mining public database strategy is time-and cost-saving,it is difficult to obtain a large number of microsatellite markers,mainly due to the limited sequence data of non-model species deposited in public databases. Based on the results in this study,we recommend two methods,microsatellite-enriched library construction method and FIASCO-colony hybridization method,for large-scale microsatellite marker development. Both methods were derived from the microsatellite-enriched strategy. The experimental results obtained from Zhikong scallop also provide the reference for microsatellite marker development in other species with large genomes.

Analysis of molecular variation in porcine reproductive and respiratory syndrome virus in China between 2007 and 2012

In the present study, 89 porcine reproductive and respiratory syndrome virus(PRRSV) isolates in China during 2007 to 2012 were randomly selected from the GenBank genetic sequence database. Evolutionary characteristics of these isolates were analyzed based on the sequences of non-struc-tural protein 2(Nsp2) and glycoprotein 5(GP5). The genetic variations of the isolates were also compared with six representative strains. The results showed that a high degree of genetic diversity exists among the PRRSV population in China. Highly pathogenic PRRSV isolates, with a discon-tinuous deletion of a 30 amino acid residue in the Nsp2 region, remained the most dominant virus throughout 2007–2012 in China. Owing to the extensive use of representative vaccine strains, natu-ral recombination events occurred between strains. Three isolates – HH08, DY, and YN-2011 – were more closely related to vaccine strains than the other isolates. Both YN-2011 and DY were the evolu-tionary products of recombination events between strains SP and CH-1R. The results of the present study provide useful information for the epidemiology of PRRSV as well as for vaccine development.

Genetic Diversity among Some Sheep Breeds in Sulaimani Governorate Using RAPD-PCR Technique

RAPD （Random amplified polymorphic DNA） markers were used to study genetic diversity among three Kurdish sheep breeds （the Karadi, Hamdani and Jaff） with the Awassi sheep breed. A total of 40 samples were typed using twenty RAPD primers. Ten out of the twenty primers had clear bands, which used to investigate the genetic variations among breeds. One of the ten primers is monomorphism. A total of 109 bands were scored, of which 46 bands （46.56%） were polymorphic and 18 of polymorphic band were unique bands. For all breeds, Nei＇s gene diversity, Shannon index, percentage of polymorphic loci and unique bands are respectively in the range of 0.32 to 0.50, 0.44 to 0.69, 31.81 to 100, and 2 to 8. Using UPGMA （unweighted pair-group method with arithmetic average） dendrogram, the three clusters, the 1st cluster branch consisted of the Karadi sheep breed, the 2nd cluster was include both of the Jaff and Hamdani sheep breeds and the 3rd one included Awassi sheep breed. These results indicated that the Karadi sheep is most genetically distant from the Awassi sheep （0.916）. The Jaff and Hamdani sheep in the 2nd cluster indicate a close relationship between them and the results indicated that the Jaff and Hamdani sheep breeds were closer to Awassi sheep breed than to the Karadi sheep breed. The dendrograms show that there are high genetic distances among sheep breeds, and were ranged from 0.223 between Hamdani and Jaff sheep breeds to 0.916 between Karadi and Awassi sheep breeds. Based on the high degree of genetic distance among the four sheep breeds it is concluded that the four sheep breeds arc independent and isolated breeds.

The complexities of female mate choice and male polymorphisms： Elucidating the role of genetics, age, and mate-choice copying

Genetic, life history, and environmental factors dictate patterns of variation in sexual traits within and across popula- tions, and thus the action and outcome of sexual selection. This study explores patterns of inheritance, diet, age, and mate-choice copying on the expression of male sexual signals and associated female mate choice in a phenotypically diverse group of Schizo- cosa wolf spiders. Focal spiders exhibit one of two male phenotypes： ＇omamented＇ males possess large black brushes on their fo- relegs, and ＇non-ornamented＇ males possess no brushes. Using a quantitative genetics breeding design in a mixed population of ornamented/non-ornamented males, we found a strong genetic basis to male phenotype and female choice. We also found that some ornamented males produced some sons with large brushes and others with barely visible brushes. Results of diet manipula- tions and behavioral mating trials showed no influence of diet on male phenotype or female mate choice. Age post maturation, however, influenced mate choice, with younger females being more likely to mate with ornamented males. A mate-choice copy- ing experiment found that, following observations of another female＇s mate choice/copulation, virgin mature females tended to match the mate choice （ornamented vs. non-ornamented males） of the females they observed. Finally, analyses of genetic varia- tion across phenotypically pure （only one male phenotype present） vs. mixed （both phenotypes present） populations revealed ge- netic distinction between phenotypes in phenotypically-pure populations, but no distinctionin phenotypically-mixed populations. The difference in patterns of genetic differentiation and mating across geographic locations suggests a complex network of fac- tors contributing to the outcome of sexual selection .

Hv-SEMIGROUP STRUCTURE ON F2-OFFSPRING OF A GENE POOL

Mendel, the father of genetics took the first steps in defining ＂contrasting characters, genotypes in F1 and F2... and setting different laws＂. The genotypes of F2 is dependent on the type of its parents genotype and it follows certain roles. Purpose of this paper is to analyze the second generation genotypes of monohybrid and a dihybrid with a mathematical structure. We use the concept of Hv-semigroup structure in the F2-genotypes with cross oper- ation and prove that this is an Hv-semigroup. We determine the kinds of number of the Hv-subsemigroups of F2-genotypes.