Macroevolutionary patterns in intragenomic rDNA variability among planktonic foraminifera

Area of Science:

• Marine biology
• Genomics
• Protistology

Background:

• Ribosomal intragenomic variability is a known genomic feature impacting diversity assessments.
• Evolutionary mechanisms and distribution of this variability within microbial groups are under-explored.

Purpose of the Study:

• To investigate intragenomic variability in planktonic foraminifera.
• To explore the evolutionary patterns and sources of this variability in this microbial group.

Main Methods:

• Analysis of 2,403 partial small subunit (SSU) ribosomal RNA sequences from 33 planktonic foraminifera species.
• Inspection of single-cell clone libraries.
• Molecular simulations to assess mutation locations.
• Phylogenetic mapping of polymorphic sites.

Main Results:

• Polymorphisms are prevalent in planktonic foraminifera species.
• Significant differences in the number of polymorphic sites were observed among different clades.
• Most mutations were found in paired regions, not impacting SSU secondary structure.

Conclusions:

• Intragenomic variability is a common trait in planktonic foraminifera with clade-specific differences.
• The observed variability is linked to the distinct nuclear and genomic dynamics of these marine protists.
• This study provides insights into the evolution and sources of intragenomic variability in planktonic foraminifera.