Inheritance And Variation Of AFLP And DNA Methylation In Cotton Introgressed Lines

The inheritance and variation of genome and DNA methylation on the parents, offsprings and population from the interspecific hybridization introgressed lines of Gossypium hirsutum including three introgressed lines with consanguinity of G.bickii and ten with consanguinity of G.thurberi,G.araburem and G.barbadense were studied by using AFLP and MSAP analysis.The main results were as follows:1.Most loci showed Mendelian inheritance,and also only three missing loci and eight novel loci showed non-Mendelian inheritance in all the 2000 AFLP loci by analysis of AFLP on the introgressed lines of G.bickii and their parents.Based on that 98%of loci in each accession directly inherited from the parents and averagely eleven loci might be directly inherited from G.bickii,lower than 0.8%of loci from G.bickii might exist in introgressed lines.2.The overall cytosine methylation level and different patterns of DNA methylation loci in introgressed lines with G.bickii consanguinity were analyzed by MSAP.The overall cytosine methylation level,which were from 22.5%to 22.7%,showed no significant difference among the three introgressed lines and their recurrent parents.The obvious differences in the putative introgressed loci and non-additive DNA methylation pattern loci were not existed among the three introgressed lines,which were ranged from 2.5%to 3.5%. Combined with the AFLP results,the similarity in both genetics and epigenetics were existed between the other two introgressed lines and their recurrent parents except the introgressed line "zhongyihong 2".3.The number of introgressed loci from the wild species was stable in the four 'introgressed generations' in the introgressed TAB types with the consanguinity of G. thurberi,G.araburem and G.barbadense.On the average,AFLP introgressed loci in the four introgressed generations was 4,6,6 and 5,respectively,while the methylation introgressed loci was 4,7,6 and 5,respectively.And both AFLP loci and MSAP pattern from G.barbadense and G.thurberi in this introgressed population could be also obviously higher than G.araburem.The better fiber quality in the early generations compared with other introgressed generations in this population could be impacted by G.barbadense and G.thurberi.4.Sequence characterization of the DNA methylation variant pattern strongly revealed that the variant fragments of DNA methylation mostly related to repeat sequences and non-coding sequences.5.The diploid species,G.barbadense and the introgressed lines could be effectively distinguished by AFLP and MSAP.Moreover,the further comparison between the two approaches indicated that MSAP could be thought to be a faithful tool in epigenetic marker.In summary,the similarity of epigenetic variation to that of AFLP genetics was also found among the intrerspecific hybridization introgressed lines and their parents in the Gossypium,while the DNA methylation levels and patterns in these materials displayed mendelian inherence.In addition,higher polymorphism and better resolution of genetic relationships among the intrerspecific hybridization introgressed lines could be revealed by MSAP compared with AFLP.According to the present and previous reports,it was further demonstrated that MSAP could be regarded as a faithful epigenetic maker.