论文部分内容阅读
Using modified cDNA RDA capitalizing on the high affinity of streptavidin for biotin and magnetic-absorption-based separation,we have obtained four bands of specifically expressed cDNA in the carrot somatic embryo deregulated for 12 h,which were designated as NR-1,NR-2,NR-3 and NR-4,respectively.As revealed by homology analysis of their DNA sequences after cloning them into pBS,remarkable homology was demonstrated in NR-2,NR-3 and NR-4 with the genes coding for LEA (late embryogenesis abundant protein),Dna J and xyloglucan endo-transglycosylase in plants.On the other hand,NR-1 showing no homology with any known sequence may have come from unknown genes.Using 32P-labeled NR-1 as probe,hybridization with cDNA fragment population has shown that we have actually cloned a new gene fragment related to radicle development.As shown by further Southern hybridization,these genes may be present in carrot genome in the form of single or low copies.