The Phenomenon Of RNA And DNA Sequence Differences At Transcriptome In The Nascent Polyploidization Of An Polyploidy Line By Goldfish×commomm Carp

Polyploidization is a phenomenon that genome increased instantaneously.Polyploidization occurred in most plants and fewer vertebrate species.Many plants that related to our lives and productions are polyploid such as hexaploid wheat,triploid seedless watermelons,tetraplont cotton and polyploid flowers such as marigold,calendula,violets and so on.Compared to the plants,polyploidization is much rarer in vertebrates including the amphibians,reptiles and fishesWhy polyploidization is much rare in extant animals than in plants?Recent study in polyploid plants show that a series of genetic and epigenetic changes occurred after the whole genome doubling.These studies based on appropriate polyploidization of plant models suggest that we need a stable polyploidization of vertebrates research model to carry out the related search.We get an polyploidy line by goldfish(?)× common carp(?)throngh the cooperation for studying The first two generations of this line are diploids,and subsequent generations are tetraploids.It's a wonderful and suitable system for studying why polyploidization in animals is rare than plants.Our previous studies showed that genome doubling of hybrids form polyploidy line by goldfish(?)X common carp(?)like plants might have brought themselves many more confusions,which same as the genome shock including changes in genetic and epigenetic level.For example,high frequency of mutations,restructuring,rearrangement,changes at transcription level,and so on.But genome shock in hybrids showed more enduring and complex than in plants.We also find that RNA polymerase is chimeric that RNA polymerase gene is combining both two sequences in goldfish and carp.According to the central dogma,whether transcription is faithful form DNA to RNA or not?Although DNA is the template of RNA,both of them are bases pairing with each other and genetic materials in DNA should be transcribed to the corresponding RNA faithfully according to central dogma,but some recent studies show the process of transcription is not completely faithful and more often results in RNA-DNA differences occurred.From above two points,whether the RNA-DNA differences mutations are magnified in polyploidy line by goldfish × common carp or not due to the impress of genome shock?Hence,we use the Sanger and next generation sequencing(NGS)to investigate the RNA-DNA differences in polyploidy line by goldfish × common carp.First,our study used Sanger sequencing method to carry out exploratory research.We selscted the plk2b gene(cell-related related)and ncoa2 gene(umorigenesis related)to PCR amplification and Sanger sequenceing of liver and testis(ovary)form parents and different offsprings.(Clones numbers are decided by different copies of every individual).According to the analysis of sequencing results,we detected the rates of RNA-DNA differences mutations of two genes are range from 0.25%to 0.77%,it is higher 2-7 times compared to the human B cells.Based on the meaningful results of two genes,we use the next genetarion sequencing data(NGS)to insight into RNA-DNA differences mutations in polyploidy line by goldfish(?)X common carp(?).We extracted DNA and RNA of kidneys from parents and offsprings and got the NGS data through Re-sequencing and RNA-seq,then we dealt with the data by variance calling,the mutation screening and classify,gene expression analysis.The analysis NGS datas show that the rate of RNA-DNA differences mutations in the polyploidy line by goldfish X common carp is 1%,and it's 10 times higher than human B cells.Four main types of RNA-DNA differences are identified within all of individuals including A?G,T?C,G?A,C?T.We seek to detail how those mutations generated based on literatures research,and we find that two RNA editing enzemys that ADAR and APOBEC may contribute to the occurration RNA-DNA difference mutations that A?G,C?T respectively.DNA damage may trigger the other tow kinds of mutations that T?C and G?A.Some hazardous substancein form environment just as ultraviolet radiation might cause the two adjacent T binding with each other and cannot do the base parring with A,so the possibility of mutation rates of T?C is increased,the Alkyl might resulted in methylation of G and give rise to the produce of G?A.In addition,the total rate of RNA-DNA difference mutations in octaploid is higher than tetraploid,this result show polyploidization seem to increase the RNA-DNA difference mutations in polyploidy.The RNA-DNA difference mutations were common riched in exon and intergenic region that correlation with gene expression regulation function.The analysis of potential relatedness between RNA-DNA difference mutations and gene expressin show that octaploid tend to have higher rate of high expression of high mutation gene than tetraploid.The result shows that some phenomenon like the high frequency of RNA-DNA difference mutations,high mutation and high expression genes in polyploidy line by goldfish(?)×common carp(?),it indicates that key changes of genome shock contained the high frequency faithless transcription in nascent polyploidization.It reminds us that polyploidy have to deal with more confusions come from RNA editing and DNA damage,this is likely to strengthen the genome shock effect and provide new clues in study about the reason why polyploidy is relatively rare in vertebrates.