CenH3 evolution in diploids and polyploids of three angiosperm genera

Area of Science:

• Plant genetics and genomics
• Epigenetics and chromatin biology
• Evolutionary biology

Background:

• Centromere specification is complex, involving more than just DNA sequences.
• The centromere-specific histone variant, CenH3, shows rapid evolution across species.
• This rapid evolution may be a coevolutionary response to evolving centromeric DNA.

Purpose of the Study:

• Investigate CenH3 evolution in angiosperms (Brassica, Oryza, Gossypium).
• Analyze nucleotide and protein diversity in diploids and allopolyploids.
• Identify evidence of diversifying selection in different CenH3 gene domains.

Main Methods:

• Characterized nucleotide and protein diversity of CenH3.
• Compared expression profiles and alternative splicing of CenH3.
• Focused on three diverse angiosperm genera: Brassica, Oryza, and Gossypium.

Main Results:

• All genera retained duplicated CenH3 copies.
• Brassica and Gossypium showed biased homoeologous expression.
• Alternative splicing significantly contributes to CenH3 diversity.

Conclusions:

• N-terminal domain diversification, not DNA binding domains, is subject to selection.
• Rapidly evolving centromeric DNA is unlikely the primary driver of CenH3 diversification.
• The functional significance of N-terminal domain evolution and alternative splicing remains unclear.