Differential evolutionary patterns and expression levels between sex-specific and somatic tissue-specific genes in...

Area of Science:

• Genomics
• Plant Biology
• Evolutionary Biology

Background:

• Understanding tissue-specific gene evolution and expression is crucial, especially beyond sex-specific genes.
• Peanut (Arachis hypogaea) is an important crop, yet its gene evolution patterns remain understudied.

Purpose of the Study:

• To identify and characterize tissue-specific genes in cultivated peanut.
• To compare the evolutionary patterns and expression levels of somatic versus sex-specific genes.

Main Methods:

• Utilized 22 RNA-sequencing (RNA-seq) datasets from cultivated peanut.
• Identified 3,191 tissue-specific genes and 38,745 common genes.
• Analyzed gene expression levels, evolutionary rates, selection signatures, and codon usage bias.

Main Results:

• Tissue-specific genes exhibited lower expression levels than common genes.
• Sex-specific genes had higher expression than somatic tissue-specific genes, with gynoecium-specific genes showing higher expression than androecium-specific genes.
• Heterogeneous duplicate gene pairs evolved faster than homogeneous pairs; somatic tissue-specific genes evolved faster than sex-specific genes, showing relaxed selection and higher codon usage bias compared to sex-specific genes.

Conclusions:

• Contrasting evolutionary and expression patterns exist between somatic and sex-specific genes in peanut.
• Findings provide novel insights into the fundamental biology and evolution of peanut.
• This study lays the groundwork for future research on gene regulation and adaptation in important crop species.