Numbering Diploid Cotton Pachytene Chromosomes Using EST By Fluorescent In Situ Hybridization

Numbering of cotton chromosome is given by chromosome length, position of centromere, elative lengths of chromosome, rm ratios. As cotton chromosome is very small, it is difficult to identify Morphologically the individual chromosome from cotton chromosome complement.Although many studies have been conducted on the karyotype of tetraploid and diploid cotton,numbered chromosome order by lengths ,but controversies still exist among different researchers.In this study,we select D-genome diploid cotton Graimondii as materials.And single copy ESTs are used as probe, distinguish thirteen pachytene chromosomes of raimondii by fluorescent in situ hybridization (FISH).The main results are as follows:1.We make slides of cotton pachytene chromosomes from pollen mother cell at first in china.We choose three ESTs from every linkage group,and thirty nine ESTs as probe aggregately.Every EST is designed prime, PCR with template DNA of raimondii genome, reclaimed, purificated and sequenced.At last,we select thirteen ESTs(866bp-1375bp) as probe together.The probes we selected are located thirteen pachytene chromosomes of raimondii respectively by FISH.2.The rDNA genes of cotton are tandemly repeated DNA.It is an important study method on the origin and evolution of tetraploid.Many researchers study its localities and copies by FISH. We design primes with sequence of 18srDNA and 5srDNA.We perform PCR with template DNA of TM-1 genome,reclaim, purification and sequence . 18SrDNA and 5S rDNA as probe located the pachytene chromosomes of raimondii.We confirm copy groups of Ghirsutum, Gbarbadense, Graimondii, G.herbaceum,and study concerted evolution of 5SrDNA in tetraploid and diploid cotton.3.We analyse karyotype of the thirteen pachytene chromosomes of raimondii first,and number chromosomes via the length of thirteen pachytene chromosomes. We compare the karyotype of pachytene and metaphase chromosomes.