作物数量遗传学基础 二、遗传力及其估算

两栖类染色体的研究，过去多使用以生殖 细胞和端蚌尾部上皮细胞为材料的水低渗压片 法^6]。然而，生殖细胞和峪蚌组织受季节的限 制颇大，所得的中期分裂相亦不甚多。随着 低等脊稚动物组织培养技术^1,2]与血液培养技 术^3]的发展，近年来已更多的使用离体培养的 细胞来进行研究。

Cloning and Characterization of Hsp70a cDNA Fragment of Dunaliella salina

The present study is to obtain heat shock protein 70a cDNA fragment from Dunaliella salina. Two pairs of degenerate primers were designed according to conserved motifs of DIDLGTT,DQGNRTTP,PAYFNDS and ATKDAG of the homologous amino acid sequences and used to amplify hsp70a cDNA fragment from heat-shock-treated Dunaliella salina by nest PCR technique. The resulting PCR products were inserted into T-vector then transformed into JM109. Ten colonies were selected to determine their sequences. Homologous analysis of the deduced amino acid sequences were performed by BLAST and subsequently compared with GenBank data. Three of ten nucleotide sequences were obtained,of which there was 372 bp coding 126 amino acids. The sequences shared high homology with hsp70a,with identity 96% to Chlamydomonas reinhardtii, 94% to Petunia, 93% to Pisumsativum, 92% to tomato, 92% to human,90% to Drosophila and 89% to yeast respectively. It can be concluded that the cloned sequence is putatively hsp70a cDNA fragment from Dunaliella salina.