Polymorphism Of Body-color And AFLP Analyses On The Scallop Chlamys Nobilis

In order to explore the degree of genetic diversity and provide a geneticimprovement of C.nobilis,survey was carried out on body color polymorphism ofC.nobilis cultivating in Liusha Bay. AFLP were applied to investigate genetic diversity infour kinds color of shell and two kinds color of adductor of C.nobilis. The main resultsare as follows：1、Survey was carried out on body color polymorphism of C.nobilis cultivating inLiusha Bay,Leizhou Byland. This experiment was conducted to provide the theoreticalreference for genetic improvement of body colors of C.nobilis. Results showed: Theresults showed that there were5954individuals from10different groups which haddifferent seed source, they can be classified as six kinds of shell color which wereOrange （62.31%）, Bordeaux-Brown （14.51%）, Purple-White （12.46%）, Orange-Purple（6.43%）, Purple-Bordeaux-Brown （3.46%） and Orange-Purple-Yellow （0.82%）.Theadductors of all populations have two colors of white, yellow and white ratio wassignificantly higher than yellow ratio（P<0.05）, the highest ratio of yellow adductor wasOrange （18.79%），which followed were Orange-Purple （14.10%）, Orange-Purple-Yellow（10.20%）, Bordeaux-Brown （5.09%）, Purple-White （4.45%） andPurple-Bordeaux-Brown （0.49%）. The gonad of mature C.nobilis have two colors ofyellow, ivory, which represent female and male. The sex ratio had correlation with thecolor of adductor, the sex ratio（♀：♂） was （63.06%：36.94%） when the adductor wasyellow and it was （50.94%：49.06%） when it was white. The study showed that Orangewas the primary shell color （P<0.05） and white was the primary adductor color （P<0.05）in C.nobilis; the colors have certain relations between shell and adductor,the ratio ofyellow adductor was highter with “yellow” in shell （P<0.05）; the ratio of yellow adductorof female had significantly higher than male （P<0.01）.2、Amplified Fragment Length Polymorphism（AFLP）technique was used to analyzethe genetic diversity and differentiation of120individuals from four culturedpopulations（30individuals perpopulation） of different shell color（Purple-Brown、Brown、Bordeaux-White and Orange）of C.nobilis．Ten pairs of AFLP primers were selected,414loci were amplified using10pairs of primers combinations and352of which werepolymorphic，and the proportion of polymorphic was85.02%. From Purple-Brown、Brown、Bordeaux-White to Orange， the polymorphic loci ratio（P）in four lines were 72.83%，86.04%，83.47%and67.35%， respectively. Nei′s gene diversity （H） were0.3071，0.3494，0.3358and0.3077，respectively，and Shannons information indexes（I） were0.4607，0.5139，0.4987and0.4525， respectively. The mean geneticdifferentiation (G_st) between four lines was0.1739. The genetic diversity amongpopulations was0.3954. The mean genetic distances (D_xy) were0.1511between PB andB，0.1720between PB and BW，0.1675between PB and O，0.1194between B andBW，0.1637between B and O，0.1255between BW and O， respectively. The clusteranalysis showed that，the genetic relationships from near to far between four shell colorslines were Bordeaux-White， Brown， Orange and Purple-Brown. There existed highergenetic diversity in each selected line, and the genetic differrernces between four familiesof F1populations were proved in the molecular way, the selection can be continue.Results of the study can provide theoretical support for the directed selection of four shellcolor lines of C.nobilis.3、Amplified Fragment Length Polymorphism（AFLP） technique was used to analyzethe genetic diversity and differentiation of60individuals from two culturedpopulations（30individuals perpopulation） of different adductor color（Red and White） ofOrange shell color of C.nobilis．Six pairs of AFLP primers were selected,247loci wereamplified using6pairs of primers combinations and198of which were polymorphic，and the proportion of polymorphic was80.16%. From Red to White， the polymorphicloci ratio （P） in two lines were80.00%and82.38%， respectively. Nei′s gene diversity（H） were0.2677and0.2479respectively， and Shannons information indexes （I） were0.4135and0.3925， respectively. The mean genetic differentiation (G_st) was0.0893. Themean genetic distances (D_xy) was0.0705. The gene flow was5.0991. There existedhigher genetic diversity and no significant difference in two populations.4、The genome DNA of two different adductor color （Red and White） of Orangeshell color of C.nobilis were scanned by64primer-combinations. Only1primer-combinations amplified1adductor color-specific markers. The relevant AFLPbands were marked and excised， reamplified， cloned and sequenced. For the AFLPmarker M1， a pair of PCR primers were designed， but the AFLP marker failedconversion to a SCAR marker. Although no adductor color-specific Ioci was found．Thedata obtained by the study provided a base for the further research of adductor colordetermination in C.nobilis.