应用RAPD技术对我国不同地域红色毛癣菌分离株的遗传多样性研究

目的探讨我国不同地域红色毛癣菌分离株的遗传多样性。方法采用随机扩增DNA多态性(RAPD)方法对来源于我国不同地域(江苏南京,山东济南,广东广州)的32株红色毛癣菌临床分离株进行DNA多态性分析。结果红色毛癣菌种内差异明显,根据遗传相似性分成三大聚类群,与地域差异及取材部位无明显相关性,而与表型具有一定相关性。结论随机扩增DNA多态性方法可用于红色毛癣菌的DNA分型,其DNA带型具有一定的遗传变异性,与菌株表型有一定关系,与地域差异、侵犯部位无明显相关性。     

Detecting signatures of inter‐regional and inter‐specific hybridization among the Chinese rhesus macaque specific pathogen‐free (SPF) population using single nucleotide polymorphic (SNP) markers

Background While rates of gene flow between rhesus and longtail macaque populations near their hybrid zone in Indochina have been quantified elsewhere, this study demonstrates that the inter‐specific introgression is not limited to the Indochinese hybrid zone but is more geographically widespread. Methods Twelve rhesus and longtail macaque populations were analyzed using single nucleotide polymorphic (SNP) loci. Results There is evidence for inter‐specific admixture between Chinese rhesus and mainland longtails, with implications for genetic diversity both in the Chinese super‐SPF population at the California National Primate Research Center and in other primate facilities. Eastern Chinese rhesus appeared more highly derived than western Chinese rhesus, and allele sharing between longtails and Chinese rhesus was not random with regard to geographic distance, but no significant nuclear genetic differences between eastern and western Chinese rhesus were detected among the 245 genic SNPs assayed. Conclusion The implications of this inter‐specific admixture for the use of Chinese rhesus and mainland longtail in biomedical research should be considered.     

Dopamine receptor D4 allele distribution in Amerindians: A reflection of past behavior differences?

The DRD4 variable number of tandem repeats (VNTR) allele distribution of 172 Guarani (Kaiowá and Ñandeva subgroups) and Kaingang Brazilian Amerindians is reported. These results are integrated with those previously obtained for this ethnic group. Allele frequencies for the three populations are within the interval observed for 15 other Native American populations and show intermediate values between those observed in Amazonia and Patagonia. Significant differences in allele distribution between recent past hunter–gatherer and agriculturalist populations are observed, with an increase of the 7R allele among hunter–gatherers (P < 0.001). Analysis of molecular variance (AMOVA) and pairwise F_ST data suggest three distinct sectors for the genetic landscape of Native South America: Andes, Center/Southeast region, and Amazonia. Common traits among hunter–gatherers such as novelty‐seeking temperament, hyperactivity, and impulsivity could have been important and advantageous in new environments during America's prehistoric colonization. Am J Phys Anthropol, 2010. © 2010 Wiley‐Liss, Inc.     

A prime inference on genetic diversity (RAPDs) in the marine fish Atherinella brasiliensis (Teleostei,Atherinopsidae) from Southern Brazil

Da Silva Cortinhas, M. C., Glienke, C., Prioli, A. J., Noleto, R. B., Matoso, D. A. and Cestari, M. M. 2010. A prime inference on genetic diversity (RAPDs) in the marine fish Atherinella brasiliensis (Teleostei, Atherinopsidae) from Southern Brazil. —Acta Zoologica (Stockholm) 91 : 242–248 As a result of the importance of Atherinella brasiliensis in estuarine environments, random amplified polymorphic DNA (RAPD) markers were used to verify the genetic diversity in A. brasiliensis from two different places in Paranaguá Bay (Paraná State) and one from the Conceição Lagoon (Santa Catarina State). Cytogenetic data have shown a high karyotypic diversity in some populations, although in others this peculiarity demonstrates rearrangements such as heterochromatinization. In the present study, a low level of genetic structuring between the samples from Conceição Lagoon compared with the others was observed through principal coordinate analysis (PCO), analysis of molecular variance and Mantel test according to 79 RAPD markers. As this specie does not perform horizontal migration and the individuals of Conceição Lagoon are isolated, three hypotheses are proposed to explain the results: (i) similar environments may show homogeneous populations not depending on the geographical distance, (ii) because vicariant events that formed the bays occurred in a recent period, the fragmentation effects over the structuring of the genetic diversity may still be low and not totally detectable by the RAPD technique and (iii) the isolation time or the number of generations may not be enough to promote a possible differentiation and genetic structuring between the specimens of these three places. The specimens of these places present a low level of differentiation and genetic structuring so we can consider them as a unique homogeneous population.     

Preimplantation genetic diagnosis of β-thalassemia using real-time polymerase chain reaction with fluorescence resonance energy transfer hybridization probes

Preimplantation genetic diagnosis (PGD) is employed increasingly to allow transfer of embryos to the uterus in assisted reproduction procedures. There are three stages of biopsy: polar bodies, one or two blastomeres from the cleavage-stage embryos, and trophectoderm cells (∼5 cells) from the blastocyst-stage embryos. Validation of polymerase chain reaction (PCR)-based assays are challenging because only limited genetic material can be obtained for PGD. In the current study, we modified a valid single-cell PCR protocol for PGD using real-time PCR assay with fluorescence resonance energy transfer (FRET) hybridization probes followed by melting curve analysis. We optimized and clinically applied the protocol, permitting molecular genetic analysis to amplify a specific region on the beta-globin (HBB) gene for a couple, carriers of two mutations: c.-78A>G and c.52A>T. Among a total of eight embryos obtained after ovarian stimulation, a single blastomere per embryo at the six- to eight-cell stage was biopsied. This PGD method showed that four embryos were unaffected, two embryos were selected for transfer, and one pregnancy was achieved. Finally, a healthy male baby was delivered at 38 weeks’ gestation. The results obtained using the new method, FRET hybridization probes, were compared with findings using an existing method, primer extension minisequencing.     

The linkage maps of Dendrobium species based on RAPD and SRAP markers

Dendrobium plants are used commonly as tonic herbs and health food in many Asian countries,especially in China.Here we report the genetic map construction of two Dendrobium species with a double pseudo-testcross strategy using random amplified polymorphic DNA (RAPD) and sequence-related amplified polymorphism (SRAP) markers.A F1 mapping population of 90 individuals was developed from a cross between D.officinale and D.hercoglossum.A total of 307 markers,including 209 RAPD and 98 SRAP,were identified and used for genetic linkage group (LG) analysis.The D.officinale linkage map consisted of 11 major linkage groups and 3 doublets,which covered 629.4 cM by a total of 62 markers with an average locus distance of 11.2 cM between two adjacent markers.The D.hercoglossum linkage map contained 112 markers mapped on 15 major and 4 minor linkage groups,spanning a total length of 1,304.6 cM with an average distance of 11.6 cM between two adjacent markers.The maps constructed in this study covered 92.7% and 82.7% of the D.hercoglossum and D.officinale genomes respectively,providing an important basis for the mapping of horticultural and medicinal traits and for the application of marker-assisted selection in Dendrobium breeding program.     

Genetic trade-off between abilities to avoid attack and to mate: a cost of tonic immobility

Consistent individual differences in correlated behaviours across contexts or situations, that is, behavioural syndromes, have recently been identified as an important factor shaping the evolution of behavioural traits, because of their potential for explaining trade-offs in behavioural responses. We examined a genetic link between abilities to mate and to avoid predation from the viewpoint of two genetically correlated behavioural traits; tonic immobility (TI), which is considered to be an antipredator behaviour, and activity levels in the red flour beetle, Tribolium castaneum. Males derived from two strains artificially selected for divergent durations of TI were used in the present study: the L strain (with longer duration and higher frequency of TI) and the S strain (shorter duration and lower frequency of TI). We found that males of the L strain had higher survival rates in predatory environments than those of the S strain, and lower mating success even in predator-free environments. To our knowledge, this is the first empirical study showing a genetic trade-off between abilities to mate and to avoid predation in relation to behavioural syndromes, using individuals exhibiting different behavioural strategies.     

Estimates of (co)variance components and genetic parameters for body weights and first greasy fleece weight in Bharat Merino sheep

(Co)variance components and genetic parameters of weight at birth (BWT), weaning (3WT), 6, 9 and 12 months of age (6WT, 9WT and 12WT, respectively) and first greasy fleece weight (GFW) of Bharat Merino sheep, maintained at Central Sheep and Wool Research Institute, Avikanagar, Rajasthan, India, were estimated by restricted maximum likelihood, fitting six animal models with various combinations of direct and maternal effects. Data were collected over a period of 10 years (1998 to 2007). A log-likelihood ratio test was used to select the most appropriate univariate model for each trait, which was subsequently used in bivariate analysis. Heritability estimates for BWT, 3WT, 6WT, 9WT and 12WT and first GFW were 0.05 ± 0.03, 0.04 ± 0.02, 0.00, 0.03 ± 0.03, 0.09 ± 0.05 and 0.05 ± 0.03, respectively. There was no evidence for the maternal genetic effect on the traits under study. Maternal permanent environmental effect contributed 19% for BWT and 6% to 11% from 3WT to 9WT and 11% for first GFW. Maternal permanent environmental effect on the post-3WT was a carryover effect of maternal influences during pre-weaning age. A low rate of genetic progress seems possible in the flock through selection. Direct genetic correlations between body weight traits were positive and ranged from 0.36 between BWT and 6WT to 0.94 between 3WT and 6WT and between 6WT and 12WT. Genetic correlations of 3WT with 6WT, 9WT and 12WT were high and positive (0.94, 0.93 and 0.93, respectively), suggesting that genetic gain in post-3WT will be maintained if selection age is reduced to 3 months. The genetic correlations of GFW with live weights were 0.01, 0.16, 0.18, 0.40 and 0.32 for BWT, 3WT, 6WT, 9WT and 12WT, respectively. Correlations of permanent environmental effects of the dam across different traits were high and positive for all the traits (0.45 to 0.98).