Japanese scallop is one of the most important cultured seashells in the world. Following about 20 years’ artificial culture, we need DNA markers for genetic research. Microsatellites recently have become popular mark...Japanese scallop is one of the most important cultured seashells in the world. Following about 20 years’ artificial culture, we need DNA markers for genetic research. Microsatellites recently have become popular markers in a variety of genetic investigations. In this research, we isolated microsatellite DNAs from the Japanese scallop Patinopecten yessoensis genome with magnetic beads. As a result, 136 positive clones were identified from 192 clones,and 179 microsatellites were found. Among the 179 microsatellites, 50.8% were perfect, 43.0% were imperfect and the rest were compound type (6.1%). Finally, 85 microsatellite primers were designed by software Primer Premier 5.0, and 40 pairs were screened; 15 loci showed polymorphism. In these microsatellite loci, genetic diversity was analysed in 2 cultured populations. The average number of allele (A) ranged from 3.27 to 3.40; the average heterozygosity (H_o) in 2 populations was 0.447 to 0.540; average excepted heterozygosity (H_e) was 0.468 to 0.493; and average polymorphism information content (PIC) was 0.443 to 0.463. The genetic distance was 0.1155 and genetic identity was 0.8909. Thirteen microsatellite loci except HLJX-028 and HJLX-031 could be used for genetic展开更多
Triploid shellfish are useful for aquaculture because of their sterility,superior growth and improved meat quality.Tetraploid are also valuable for 100% producing triploids through mating with diploid.We tested polypl...Triploid shellfish are useful for aquaculture because of their sterility,superior growth and improved meat quality.Tetraploid are also valuable for 100% producing triploids through mating with diploid.We tested polyploid induction in Japanese scallop,Patinopecten yessoensis,by inhibiting polar body Ⅰ (PB group) and both polar bodyⅠandⅡ (PPB group) in newly fertilized eggs.Cytochalasin B (0.6 mg/L) was applied at 11～22 min post fertilization (PF),and terminated in PB group when polar body Ⅰ was released about 70% in untreated eggs,in PPB group when polar lobe was observed in control group.The treatment and its control were repeated 5～7 times using different pairs of parents.The ploidy was determined by counting chromosome number at embryo stage,and then was detected by flow cytometry (FCM) at larvae stage and juvenile stage.\;In PB group,aneuploid (31.13%),triploid (3.96%),tetraploid (17.46%) and pentaploid (46.65%) embryos were produced,and in PPB groups,pentaploid embryos became higher (56.2%),triploid and tetraploid were 2.42% and 9.11%.At day 3 PF,the larvae showed tetraploid,pentaploid and aneuploid peaks through checking with FCM in PB group,and showed mainly higher pentaploidy peak in PPB groups.However,at day 14 PF diploids were mainly left,sometimes with small triploid peak.It suggested that most tetraploid,aneuploid and pentaploid larvae were died within the first two weeks PF.At three months PF,a few diploid juveniles were harvested in three control groups.Only 12 juvenile scallops were harvested in one of treated group (PB-7),and 11 of them died accidentally,the alive one in treated group was triploid through checking with FCM.展开更多
文摘Japanese scallop is one of the most important cultured seashells in the world. Following about 20 years’ artificial culture, we need DNA markers for genetic research. Microsatellites recently have become popular markers in a variety of genetic investigations. In this research, we isolated microsatellite DNAs from the Japanese scallop Patinopecten yessoensis genome with magnetic beads. As a result, 136 positive clones were identified from 192 clones,and 179 microsatellites were found. Among the 179 microsatellites, 50.8% were perfect, 43.0% were imperfect and the rest were compound type (6.1%). Finally, 85 microsatellite primers were designed by software Primer Premier 5.0, and 40 pairs were screened; 15 loci showed polymorphism. In these microsatellite loci, genetic diversity was analysed in 2 cultured populations. The average number of allele (A) ranged from 3.27 to 3.40; the average heterozygosity (H_o) in 2 populations was 0.447 to 0.540; average excepted heterozygosity (H_e) was 0.468 to 0.493; and average polymorphism information content (PIC) was 0.443 to 0.463. The genetic distance was 0.1155 and genetic identity was 0.8909. Thirteen microsatellite loci except HLJX-028 and HJLX-031 could be used for genetic
文摘Triploid shellfish are useful for aquaculture because of their sterility,superior growth and improved meat quality.Tetraploid are also valuable for 100% producing triploids through mating with diploid.We tested polyploid induction in Japanese scallop,Patinopecten yessoensis,by inhibiting polar body Ⅰ (PB group) and both polar bodyⅠandⅡ (PPB group) in newly fertilized eggs.Cytochalasin B (0.6 mg/L) was applied at 11～22 min post fertilization (PF),and terminated in PB group when polar body Ⅰ was released about 70% in untreated eggs,in PPB group when polar lobe was observed in control group.The treatment and its control were repeated 5～7 times using different pairs of parents.The ploidy was determined by counting chromosome number at embryo stage,and then was detected by flow cytometry (FCM) at larvae stage and juvenile stage.\;In PB group,aneuploid (31.13%),triploid (3.96%),tetraploid (17.46%) and pentaploid (46.65%) embryos were produced,and in PPB groups,pentaploid embryos became higher (56.2%),triploid and tetraploid were 2.42% and 9.11%.At day 3 PF,the larvae showed tetraploid,pentaploid and aneuploid peaks through checking with FCM in PB group,and showed mainly higher pentaploidy peak in PPB groups.However,at day 14 PF diploids were mainly left,sometimes with small triploid peak.It suggested that most tetraploid,aneuploid and pentaploid larvae were died within the first two weeks PF.At three months PF,a few diploid juveniles were harvested in three control groups.Only 12 juvenile scallops were harvested in one of treated group (PB-7),and 11 of them died accidentally,the alive one in treated group was triploid through checking with FCM.
