Regulatory Divergence between Parental Alleles Determines Gene Expression Patterns in Hybrids

siti resmi;

Both hybridization and all opolyploidization generate novel phenotypes by conciliating divergent genomes and regulatory networks in the same cellular context. To understand the rewiring of gene expression in hybrids, the total expression of 21,025 genes and the allele-specific expression of over 11,000 genes were quantified in interspecific hybrids and their parental species, Coffe a canephora and Coffe aeugenioides using RNA- seqtechnology. Between parental species,cis-and trans-regulatory divergences affected around 32% and 35% of analyzed genes, respectively, withnearly 17% of them showing both. The relative importance of trans-regulatory divergences between both species could be related to their low genetic divergence and perennial habit. In hybrids, among divergently expressed genes between parental species and hybrids, 77% was expressed like one parent (expression level dominance), including 65% like C. eugenioides. Gene expression was shown to result from the expression of both all eles affected by inter twin edparental trans-regulatory factors.A strong impact of C.eugenioides trans-regulatory factors on the up regulation of C.canephora all eles was revealed. The gene expression patterns appeared determined by complex combinations of cis- andtrans-regulatory divergences. In particular, the observed biased expression level dominance seemed to be derived from the asymmetric effects of trans-regulatory parental factors on regulation of alleles. More generally, this study illustrates the effects of divergent trans-regulatory parental factors on the gene expression pattern in hybrids. The characteristics of the transcriptional response to hybridization appear to be determined by the compatibility of gene regulatory networks and therefore depend on genetic divergences between the parental species and their evolutionary history