Phenotypic evolution through variation in splicing of the noncoding RNA COOLAIR

Area of Science:

• Plant genetics
• Molecular biology
• Evolutionary biology

Background:

• Natural variations in flowering time are common in Arabidopsis thaliana.
• Noncoding cis polymorphisms in FLOWERING LOCUS C (FLC) contribute to these variations.
• The functional impact of noncoding polymorphisms is not fully understood.

Purpose of the Study:

• To investigate the functional consequences of a natural intronic polymorphism in the FLC gene.
• To understand how noncoding polymorphisms affect gene expression and phenotypic traits.

Main Methods:

• Analysis of natural polymorphisms in Arabidopsis thaliana accessions.
• Investigating the effect of a specific intronic polymorphism on FLC expression.
• Studying the splicing of the FLC antisense transcript COOLAIR.
• Examining cotranscriptional mechanisms involving nascent transcript capping.

Main Results:

• A single natural intronic polymorphism alters the splicing of the FLC antisense transcript COOLAIR.
• This altered antisense splicing leads to increased FLC expression.
• Increased FLC expression is mediated by a cotranscriptional mechanism involving nascent transcript capping.

Conclusions:

• Noncoding polymorphisms can have significant functional consequences.
• Single nucleotide polymorphisms in noncoding regions can drive phenotypic evolution.
• Modulation of noncoding transcripts by polymorphisms is a key evolutionary mechanism.