Morphological Characteristics And Mitochondrial Genome Comparison Of Nile Tilapia,Blue Tilapia And Their Reciprocallycrossed Hybrid Stocks

Tilapia is favored by farmers because of its rapid growth and high yield,and it is one of the most important freshwater aquaculture species in the world.His tilapia(Oreochromis nil-oticus ♀ x Oreochromis aureus came here)(are jiaozi,generation)is currently one of the main varieties of tilapia aquaculture,the farming quantity20% ～ 30% of the amount of total tilapia aquaculture,it is made up of Nile tilapia as female parent and oriali tilapia interspecific hybridization of male parent,the advantage of the male rate is high,can reach more than 95%,at the same time fast growth,products are miscellaneous,hypoxia tolerance,individual large,yield high,high fat full.The hand in a generation(Oreochromis aureus ♀ x Oreochromis niloticus came)is oriali tilapia as female parent and Nile tilapia as male parent interspecific hybrids,because the male rate is not high and in terms of growth rate does not have beyond the edge of the parents,therefore,no application value in the production,but can be used as good material for studying the genetics.This study with Nile tilapia,oriali tilapia and hand in one generation,jiaozi,as the research object,by comparing the morphological characteristics and mitochondrial genome data to study its hybrid genetic variation of relationship between children and parents,related research can be used for the rich fish mitochondrial genome database,for the comparative study of the molecular structure of mitochondrial genome,gene composition and arrangement the cumulative data,hope with Nile tilapia,oriali tilapia and its positive and reverse hybridization generation son as a model species to study the effect of hybrid event of tilapia mitochondrial genetic regularity,fish mitochondrial genetic regularity are discussed.The main contents and conclusions of this paper are as follows:1.Statistical analysis of the morphological characteristics of Nile tilapia,Blue tilapia and their positive and negative hybrid generation.The results showed that there was a small difference in morphological characteristics between the parents,and the positive and negative hybrid generation groups were basically between the two in appearance due to the influence of parental genetic law,and the similarity between the positive and negative hybrid generation and the parents was higher than that of the parents of Nile tilapia.2.The Nile tilapia,oriali tilapia and its positive and reverse hybridization generation of mitochondrial Co Ⅰ gene,Comparative analysis of Cytb gene and d-loop region.The results showed that the sequence alignment of the 18 anticrossbred generations and the female parents of tilapia was basically consistent in the three genes,and the nucleotide sequence homology reached more than 99.9%.The phylogenetic tree was constructed for the anticrossbred generations,and it was found that the anticrossbred generations were in the same branch as the female parents of tilapia.18 tail is jiaozi,generation of eight tail and male parent oriali tilapia in the sequence alignment of three genes,the eight tail and male parent oriali tilapia nucleotide sequence homology of 99.5% or more,were the Nile tilapia nucleotide sequence homology is above 90.1%,only higher than were the Nile tilapia nucleotide homology.The phylogenetic tree was constructed based on three genes for the generation of 18 ceutrons,and it was found that the generation of 8 ceutrons was in the same branch as that of the paternal parent,and the generation of the orthogonum was derived from the paternal line in mt DNA inheritance.3.Comparative study on the mitochondrial genome of the orthodontic generation and its parents.Results show that the tail is jiaozi,18 in 10 of his generation tail in 13 protein-coding genes,2 r RNA genes,22 t RNA gene nucleotide sequence homology analysis found that the tail is jiaozi,generation and 10 female parent the nucleotide homology of Nile tilapia was much higher than that with male parent oriali tilapia homology,show the characteristics of strict maternal lineage.In addition,8 out of the 18 orthodontic generation of tilapia have more than 99.7% nucleotide sequence homology analysis of the two r RNA genes with their father,which is higher than that with their mother,Nile tilapia.The eight tail is jiaozi,generation andmale parent oriali tilapia in 22 t RNA genes reached 95.9% ～ 100% in the nucleotide sequence homology analysis,were the nucleotide homology of Nile tilapia only reached 92.6%,higher than that of its female parent Nile tilapia nucleotide sequence homology,eight in the tail and male parent oriali tilapia in 22 t RNA gene nucleotide sequence homology of 100% has 14.For18 tail is jiaozi,generation to construct phylogenetic tree,found that 10 tail is jiaozi,generation and maternal Nile tilapia in the same,there are eight tail and male parent oriali tilapia in the same,that the tail is jiaozi,generation and male parent closer affinity,paternal genetic phenomenon exists in the level of mt DNA,this study is jiaozi,generation of paternal genetic phenomenon occurring probability of 44.4%.4.Comparative study on the mitochondrial genome of the anticrossbred generation and its parents.The results showed that the base composition of the 18 backcross generations was basically the same as that of the mother and the codon use of the protein-coding genes were basically the same,and the homology of the 18 backcross generations in the nucleotide sequences of the 2 r RNA genes and 22 t RNA genes was 100%.The phylogenetic tree constructed from 18 backcross generations shows that all the 18 backcross generations are in the same branch as the female parent of Nile tilapia,indicating that the 18 backcross generations are more closely related to the female parent,which is strict maternal inheritance at the mt DNA level.To sum up,in terms of morphological characteristics,the positive and negative hybrid generation is between the parents in appearance.In terms of mitochondrial genome,the reverse crossing generation is extremely similar to the maternal oriya tilapia in genetic relationship,showing strict matrilineal inheritance,while the normal crossing generation has a certain amount of paternal inheritance,and the probability of paternal inheritance is far higher than what has been reported so far,reaching 44.4% of the detected population.The high proportion of paternal inheritance indicates that the cause of paternal inheritance is likely to be caused by hybridization and species-specific(not present in reverse cross combinations).This study analyzed the biological characteristics of Nile tilapia,oreia tilapiaand their progeny from two aspects of morphological characteristics and mitochondrial genome,and accumulated data for the research of mitochondrial inheritance rules.