Structural and Functional Evolution of Genes in Conifers

Download or read book Structural and Functional Evolution of Genes in Conifers written by Juliana Stival Sena and published by . This book was released on 2017 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: Technical advances have accelerated the structural and functional exploration of conifer genomes and opened up new approaches to study their physiology and adaptation to environmental conditions. This thesis focuses on the evolution of conifer genes and explores (i) the genomic factors that have impacted the evolution of gene structure and (ii) the evolution of a large gene family involved in drought tolerance, the dehydrins. The analysis of gene structure was based on white spruce (Picea glauca [Moench] Voss) sequence data from BAC clones, the genome assembly and the gene space obtained from sequence capture. Through comparative analyses, we found that conifers presented more intronic sequence per gene than most flowering plants (angiosperms) and that the average intron length was not directly correlated to genome size. We found that repetitive elements, which are responsible for the very large size of conifer genomes, also affect the evolution of exons and introns. In the second part of the thesis, we undertook the first exhaustive analysis of the dehydrin gene family in conifers. The phylogenetic analyses indicated the occurrence of a series of gene duplications in conifers and a major lineage duplication, which caused the expansion of the dehydrin family in the genus Picea. Conifer dehydrins have an array of modular amino acid structures, and in spruce, these structures are particularly diverse and are associated with different expression patterns in response to dehydration stress. Taken together, our findings suggest that the evolution of gene structure is dynamic in conifers, which contrast with a widely accepted slow rate of chromosome evolution. They further indicate that the expansion and diversification of adaptation-related genes, like the dehydrins in spruce, may confer the phenotypic plasticity to respond to the environmental changes during their long life span.