The Linkage Mapping In Zhikong Scallop Chlamys Farreri And Bay Scallop Argopecten Irradians

AFLP (Amplified fragment length polymorphism) and SSRs (simple sequencerepeats) were used for the population genetic analysis of Zhikong scallop Chlamysfarreri and Bay scallop Argopecten irradians. Genetic maps of C. farreri and A.irradians were constructed with AFLP and SSR markers, using their full-sib familywith F1 progeny respectively. Seven AFLP primer pairs were used for the genetic analysis of the naturalpopulation and hatchery stock of C. farreri. The mean proportions of polymorphicfragments amplified from the natural population and hatchery stock were 75.6% and72.8% respectively, and the average heterozygosities were 0.226 and 0.209respectively. The inbreeding index (Fst) between the two populations was 0.0386 andthe genetic distance between them was 0.0271. The genetic diversity of hatchery stockwas lower than that of natural population, but there was still no significantdifferentiation between two populations. Eleven simple sequence repeats (SSRs) derived from expressed sequence tags(ESTs) were employed to investigate the genetic variation level of A. irradianspopulations. The average heterozygosities (He) of natural American bay scalloppopulation (0.4465) were higher than that of the cultured stock in north (0.4331) andsouth (0.3984) Chinese coast. A loss of nearly ten of forty-fifth alleles (23%) wasobserved in the Chinese hatchery Stocks. The reduced allelic diversity and the declineof average heterozygosities demonstrated that there was an obvious depression ofgenetic variability in the cultured stocks. Genetic maps of C. farreri were constructed using AFLP markers and a full-sibfamily with 60 progeny. A total of 603 segregating AFLP markers were obtained, iii王玲玲 栉孔扇贝和海湾扇贝遗传连锁图谱的构建研究 博士学位论文with 42 markers showing significant (p < 0.05) segregation distortion. The male mapcontained 166 informative AFLP markers in 23 linkage groups covering 2468 cM.The average distance between markers was 17.2 cM. The female genetic mapconsisted of 198 markers in 25 linkage groups spanning 3130 cM with an averageinter-marker spacing of 18.1 cM. Five shared linkage groups, ranging from 61.1 to162.5 cM, were identified between the male and female maps, covering 431 cM. AFLP and SSR markers were analyzed in the mapping population of bay scallopArgopecten irradians with 97 individuals. Fifty seven AFLP primer pairs produced3504 fragments, of which 542 (15%) were polymorphic in the mapping population.Among these polymorphic markers, 203(37%) and 187(34%) were segregating fromfemale and male parents respectively, while 152 markers from both two parents.Twenty five segregation markers were identified in the SSR analysis, 9 and 15 wereheterozygous in the female and male parent respectively. In all the 567 segregatingAFLP and SSR markers obtained, 121 showed segregation distortion, withheterozygote deficient in 77 loci. The common map consisted of 99 AFLP markers in14 linkage groups covering 2468 cM. The average space between markers was17.0cM. The female genetic map included 150 markers in 20 linkage groups spanning2131.1cM with 16.4cM per marker. The male map contained 151 markers in 20linkage groups, covering 2055.9 cM. The observed coverage was 77.4% for thecommon map, 78.6% for female map and 76.4% for the male map. The comparisonbetween male and female map of bay scallop with SSR markers (MSB6721) showedone pairs of homologous linkage groups. A few distorted maskers were foundclustering on male map (LG2, LG7, LG19), female map(LG3, LG6, LG15) andcommon map (LG3, LG4, LG5, LG7, LG12), indicating the presence of recessivelethal genes in the mapping family.