Preliminary Study On Molecular-Assisted Breeding Of Pteria Penguin

Penguin pearl oyster(Pteria penguin),also known as Winged pearl oyster,belongs to the Mollusca,Bivalbia,Pteria.Due to the large size,fast growth rate,less disease,strong environmental adaptability,and strong pearl secretion,the penguin pearl oyster has become the main oyster species for cultivating large seawater shell pearls and free round pearls in tropical and subtropical regions of our country.In this study,the first-year-old penguin pearl oyster was used as the research object to study the correlation between its morphological traits and quality traits,and then the selection and optimization of genomic DNA acquisition methods were carried out.Using the obtained high-quality DNA as a template,a highly polymorphic microsatellite locus of penguin pearl oyster was developed based on the microsatellite markers developed by predecessors and transcriptome library,and the association analysis between the microsatellite marker and phenotypic traits of penguin pearl oyster was carried out.Molecular genetic marker-assisted selection breeding provides theoretical basis and reference,which is of great significance to promote the sustainable and healthy development of our country’s pearl industry.The main findings are as follows:1.Established a genomic DNA extraction method from penguin pearl oyster shell—kit-OSE combination method,Although the newly developed genomic DNA extraction method is inferior to mantle DNA in terms of extraction efficiency and purity,this method can obtain high purity penguin pearl shell genomic DNA without affecting the survival rate of individuals.2.The correlation and path analysis results of the growth traits of the penguin pearl oyster show that:The morphological traits of the penguin pearl oyster shell length and shell height are significantly correlated with the gross weight of the quality traits(P<0.05);The shell width of morphological traits has a very significant correlation with the gross weight of quality traits(P<0.01).The order of the direct effects on the gross weight of the penguin pearl oyster is:shell length X1(0.3845)>shell height X2(0.3426)>shell width X3(0.3256);The largest indirect effect on gross weight is the indirect effect of shell width through shell length(0.2516),followed by the indirect effect of shell height through shell length(0.2267),and the smallest indirect effect of shell height through shell width(0.1943).Multivariate regression analysis was carried out with the morphological traits(shell length,width,height of the shell)of pearl oyster penguin as the independent variables and the gross weight of the yield traits as the dependent variable,and the multiple linear regression equation of each morphological trait against the gross weight was obtained:Y=-20.79279+0.2059*X3+0.3413*X1+0.6314*X2(R~2=0.8237).Therefore,when the artificial selection of penguin pearl oysters uses gross weight as the breeding target,shell width should be the first choice for 1st-year-old oysters,and the collaborative selection of shell length should be strengthened.3.Development and screening results of SSR microsatellite markers for penguin pearl oyster:Three highly polymorphic microsatellite loci(QEB-D15,QEB-C54 and QEB-C65)were obtained based on the previously developed SSR markers,and two highly polymorphic microsatellite loci(CL-232 and QEB-C65)were obtained based on transcriptome library screening.UN-4652).The correlation analysis of the phenotypic traits of Penguin pearl oyster using 5 microsatellite loci found that:The correlation coefficient between the site QEB-D15 and the shell width was 0.021(p<0.01),which was extremely significant;the correlation coefficient between the site CL-232 and the shell width was 0.167(p<0.01),and the correlation was extremely significant.Analysis of the correlation between genotype and phenotypic traits of 5microsatellite loci found that:The genotype 219/219 in QEB-C54 may be the dominant genotype.The genotype of QEB-C65 at locus 174/180 is the dominant genotype,which is positively correlated with phenotypic traits shell length,shell width and gross weight;the genotype of 174/174 may be the inferior genotype,which is negatively correlated with phenotypic traits shell length,shell width and gross weight The genotype 157/174 in CL-232 may be the dominant genotype,which is positively correlated with phenotypic traits shell length,shell width and gross weight.The genotype 177/192 may be the inferior genotype,which is negatively correlated with phenotypic traits shell length,shell width,shell height and gross weight.The genotype of 249/249 in locus UN-4652 may be the dominant genotype,which is positively correlated with phenotypic traits shell length,shell width,shell height and gross weight..The genotype 252/273 may be the inferior genotype,which is negatively correlated with phenotypic traits shell length,shell width and gross weight.