Analysis of evolutionary rate heterogeneity in lichenized fungi

2016 Fiscal Year Final Research Report

• Project/Area Number: 15K14582
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Evolutionary biology
• Research Institution: The Graduate University for Advanced Studies
• Principal Investigator: SATTA Yoko 総合研究大学院大学, 先導科学研究科, 教授 (20222010)
• Research Collaborator: KONO Mieko
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: 同義置換速度の不均一性 / 負の２項分布 / 祖先集団サイズ / オーソログとパラローグ / ガンマ分布

Outline of Final Research Achievements

The heterogeneity of the mutation rate within a genome has been known for animals, plants, and bacterias, but the heterogeneity in fungal genomes has not been fully understood. Recently, our group found the presence of a large variation in the per-site synonymous divergences among four genes between two lichens, Usnea hakanensis and U. bismolliuscula. In this study we aim to analyze the generality of this heterogeneity in their genomes and to examine their causes. Synonymous divergences of nucleotide sequences from 101 loci from two species revealed a large range of divergences from 0.046 to 0.337. Several statistical tests concluded that this range was caused by the heterogeneity of synonymous substitution rates among loci. The extent of rate heterogeneity was estimated to be 0.176 +- 0.413 /site/unit time. In future, we will examine biological causes for this heterogeneity by investigating the relationship with codon usages, gene expression and methylation.

Free Research Field

ゲノム進化学