Project description:The changes in the expression of proteins in the eggs of C. alburnus-B and C. alburnus-A at four time points (unfertilized, and 0, 0.5 and 1 h postfertilization, n=3) were quantified by TMT-based proteomics, and the changes in the expression of proteins in the egg envelopes of C. alburnus-B and C. alburnus-A at 1 h after fertilization were quantified by label-free proteomics.
Project description:Nucleolar dominance is an epigenetic phenomenon that occurs in interspecific hybrids and involves the expression of 45S rRNA genes inherited from one progenitor due to the silencing of the other progenitor's rRNA genes. In this paper, changes in the genetics and expression of 45S rRNA genes in F1 and F2 hybrid progeny of blunt snout bream (BSB, Megalobrama amblycephala)?×?topmouth culter (TC, Culter alburnus) are investigated.The 45S rDNA loci were analyzed by cloning, RT-PCR and sequencing methods. The results show that nucleolar dominance patterns differ in the F1 and F2 hybrids. In the F1 hybrids of BSB?×?TC, all the tested individuals inherited and expressed the 45S rRNA genes of both BSB and TC, indicating that nucleolar dominance is not established in the F1 hybrids. However, in the F2 hybrids of BSB?×?TC, five patterns are observed. Pattern 1 inherits and expresses only the 45S rRNA gene of BSB. Pattern 2 inherits the 45S rRNA gene from both BSB and TC, but only expresses the 45S rRNA of BSB. Pattern 3 inherits and expresses the 45S rRNA gene from both BSB and TC. Pattern 4 inherits the 45S rRNA gene from both BSB and TC, but only expresses the 45S rRNA gene of TC. Pattern 5 inherits and expresses only the 45S rRNA gene of TC.Nucleolar dominance shows distinctive patterns in intergeneric hybrids of BSB?×?TC. It is not established in F1 hybrids and is random in F2 hybrids. This study provides new insights into the phenomenon of nucleolar dominance in genetic hybrids in vertebrates.
Project description:Hybridization drives rapid speciation by shaping novel genotypic and phenotypic profiles. Genomic incompatibility and transcriptome shock have been observed in hybrids, although this is rarer in animals than in plants. Using the newly sequenced genomes of the blunt snout bream (Megalobrama amblycephala [BSB]) and the topmouth culter (Culter alburnus [TC]), we focused on the sequence variation and gene expression changes in the reciprocal intergeneric hybrid lineages (F1-F3) of BSB × TC. A genome-wide transcriptional analysis identified 145-974 expressed recombinant genes in the successive generations of hybrid fish, suggesting the rapid emergence of allelic variation following hybridization. Some gradual changes of gene expression with additive and dominance effects and various cis and trans regulations were observed from F1 to F3 in the two hybrid lineages. These asymmetric patterns of gene expression represent the alternative strategies for counteracting deleterious effects of the subgenomes and improving adaptability of novel hybrids. Furthermore, we identified positive selection and additive expression patterns in transforming growth factor, beta 1b (tgfb1b), which may account for the morphological variations of the pharyngeal jaw in the two hybrid lineages. Our current findings provide insights into the evolution of vertebrate genomes immediately following hybridization.
