Sex and U.

Area of Science:

• Genetics
• Evolutionary Biology
• Genomics

Background:

• The genomic rate of deleterious mutation (U) is a key parameter in evolutionary genetics.
• Understanding U is essential for resolving unsettled problems in genetics and determining the role of selection in evolution.
• Previous estimates of U in multicellular eukaryotes have varied significantly.

Purpose of the Study:

• To review and synthesize recent progress in measuring the genomic rate of deleterious mutation (U) in multicellular eukaryotes.
• To compare different methodologies for estimating U and discuss their limitations.
• To highlight the importance of direct mutation rate measurements.

Main Methods:

• Indirect estimation of U using comparative genomics (e.g., human-chimpanzee pseudogene comparison).
• Estimation of U based on synonymous protein-coding site comparisons in model organisms (e.g., Drosophila).
• Direct observation of new mutations in experimental populations (e.g., humans, Caenorhabditis elegans).

Main Results:

• Indirect estimates for hominoids suggest U > 3.
• Estimates for Drosophila based on synonymous sites suggest U < 0.1, potentially underestimated.
• Direct mutation rate measurements in humans and C. elegans yield high estimates.

Conclusions:

• Discrepancies in U estimates highlight methodological challenges.
• Direct observation of mutations provides a more reliable measure of U.
• High mutation rates in some eukaryotes have significant implications for evolution and genetic disease.