The Genetic Analysis And The Transcriptome Analysis Of The Formation Mechanism In The New Mutant Ellipsoid Egg Of Bombyx Mori

The genetic and molecular machnisms of the egg shapes in the silkworm are one of the research hotspots recently.Our research group has newly found an ellipsoid egg mutant which is called Nistari^elpin the Nistari silkworm strain in 2017.The ratio of the long axis with the minor axis of the eggtype in this mutant is 1.7,which is obviously higher than the normal eggtype of 1.26.And its hatching rate is 59.49%,which is far below the normal eggtype of 86.43%.This article makes the normal eggtype the control group and performs the RNA-Seq of the ovarian samples of the ellipsoid eggtype with the normal eggtype in the first 3 days of the pupal stage to find the relative differential expressed genes and their pathways of the ellipsoid eggtype.Finally,we have pricipally acquired the following 3 results:1.The genetic analysis has indicated that the inheritable character of the Nistari^elpellipsoid eggtype is recessive and this eggtype follows pseudo-maternal inheritance of the silkworm eggshell character.The recessive genes which control the characters of the Nistari^elpellipsoid eggtype with Bts045^elpellipsoid eggtype are different,and they maybe in the same linkage group.2.In this study,the normal eggshape and the ellipsoid eggshape of the Nistari strain were used as materials.RNA-Seq was carried out for the ovaries in the first three days of pupation using the high-throughput sequencing technology.A total of 153.66 Gb of filtered data was obtained.The 23366 Genes and 35798 m RNAs were predicted,and374 DEGs,including 131 up-regulated and 243 down-regulated genes,were screend in 3 groups.GO and KEGG enrichment analysis indicated that the function of DEGs mainly involved in“proteolysis”,“DNA metabolism processes”,and“euchromatin,heterochromatin”.Trend analysis showed that the gene activity of the ellipsoid egg group in the transcription level was more active than the normal egg group,especially on 3 day of the pupation.The results of WGCNA analysis showed that the gene expression pattern was divided into 6 modules,2 of which showed the specificity of the gene expression,and 9 hug genes were detected,the functions of which included the participation in translation initiation factor coding,protein denisty regulation,post-translation modification and energy conversion,and so on.3.We have also found 5 key genes except the 9 hub genes through the RNA-Seq:the Drosophila epithelial growth factor Keren,the dorsal-ventral developing gene Capicua,the homeobox gene Mirror,egg anterior information factor Dpp and the serine protease gene Rhomboid.The dorsalized eggtype would appear through the interaction of these 5 key genes,which is called the ellipsoid eggtype in the silkworm.In conclusion,the research has found the key genes of the ellipsoid eggtype mutant in the Nistari^elpstrain and this finding will offer the reference direction to study the specific reasons of the ellipsoid eggtype.