Studies On Heredity Characteristics Of The Autotetraploid F₂

Distant hybridization can effectively increase the heredity and variation of their offspring.By this way,offspring of different ploidy types were obtained including autotetraploid and allotetraploid.By the way of distant hybridization,we conducted the hybridization between different subfamilies Red crucian carp and blunt snout bream,to set up an autotetraploid fish line.This research shows the characteristic of components and reproduction,heredity and variation of autotetraploid F2.1.By the karyotype analysis conducted in chromosomes of Red crucian carp,blunt snout bream,allotetraploid F₁ and autotetraploid F₂,we found that there were no submetacentric chromosome specific to blunt snout bream in the autotetraploid F₂.Then we used the Red crucian carp-specific repeated gene sequence?No.:JQ086761?as the probe for FISH?Fish in situ hybridization?technique which could effectively distinguish the chromosomes of Red crucian carp,blunt snout bream and allotetraploid F₁ and autotetraploid F₂.Using this probe to analyse the heredity components of autotetraploid F₂,we proved that all chromosomes of autotetraploid F₂ were originated from Red crucian carp meaning that it contains 4 sets of Red crucian carp chromosomes.2.Through amplification and sequencing of Hox gene,we aimed at revealing genetic affinity and variation among autotetraploid F₂,allotetraploid F₁ and their original parents?Red crucian carp and blunt snout bream?and demonstrating at a molecular level that autotetraploid F₂ genetic material come from both original parental Red crucian carp and original parental blunt snout bream.3.By parafin section conducted in gonad during the reproduction season,we found that male and female autoetraploid F₂ could produce normal sperms and eggs.Similarly,through electric mirror scanning we also found that its ligand was normal,the diameter of which was almost larger as that of diploid fishes.This could further prove that the autotetraploid F₂ was able to produce diploid ligand which offer origin for the production of triploid,all of which played an important role in heredity breeding.