Recombination In The First Generation Of Grass Carp(♀)×Blunt Snout Bream(♂)Hybrids Strain

Fish distant hybridization is a cross between two different kinds of fish. Their parent belong to different species, different subfamily, different family. The hybrid offspring’s formation of diploid and polyploid is an important part in the process of evolution. Hybrids can integrate the advantages of parents that to show superiority in growth rate, survival rate, disease resistance and so on. Recombination is new combination of genes that not occur in parents. Recombination can urge the diversity of gametes, it can promote the formation of new species and drive evolution.This experiment use grass carp(GC) as female and Blunt snout bream(BSB) as male to hybridize and form the first generation: diploid hybrids and triploid hybrids. Transcriptome is a collection of transcript in transcriptional cells. It’s including ribosomal RNA, messenger RNA, non-coding RNA, tRNA and have very important significance to the organism. We select five genes which have genetic recombination by analysing database of transcriptome which from Huada company. In there, we use the tool of bioinformatics. Using mRNA sequences to designing primers and DNA of grass carp、blunt snout bream、2ncf 、3ncf as template, we can conduct PCR amplification. The sequence comparison genes display 2ncf and 3ncf nucleotide substitution and exchange reorganization phenomenon for its parents. There is upf3 b genes recombination crossover recombination occurs mainly in the region of the intron, first half of the nucleotide sequence is consistent with grass carp, the latter part of the nucleotide sequence is consistent with the blunt snout bream. Upf3 b join the process of transcriptional control, it can effectively sweep away defects in cell protein which may lead to lethal damage. Recombination in the region of the introns which have significance to the steady formation of hybrid system. Upf3 b have higher GC content compare to others, so we think there is a connection between recombination and GC content. GC content changes may affect the occurrence of recombination which promote the evolution of the gene and the formation of new species.Diploid hybrid which use ordinary grass carp(2n=48) as female and Blunt snout bream(2n=48)as male have 48 chromosome, one comes from the grass carp, another comes from the blunt snout bream. Tripoid hybrid have 72 chromosome, two come from grass carp, one comes from Blunt snout bream. One of the largest chromosome of hybrids come from blunt snout bream. We make karyotype analysis of diploid hybrid and tripoid hybrid, and the karyotype of diploid hybrid is 18M+25SM+5ST,and the karyotype of tripoid hybrid is 27M+37SM+8ST. The study of chromosomes have an important significance to knowing the genetic form of diploid hybrid and tripoid hybrid.