The genetic equidistance phenomenon at the proteomic level

Area of Science:

• Molecular Evolution
• Genomics
• Bioinformatics

Background:

• The field of molecular evolution originated from protein sequence alignments in the 1960s.
• The genetic equidistance result was an early, unexpected finding that inspired the molecular clock hypothesis.
• Misinterpretations led to the universal molecular clock being viewed as a mutation rate phenomenon rather than a maximum distance phenomenon.

Purpose of the Study:

• To investigate the universality of the genetic equidistance result.
• To re-evaluate the concept of the molecular clock in light of maximum distance phenomena.
• To provide evidence for the maximum genetic diversity (MGD) hypothesis.

Main Methods:

• Performed proteome-wide studies analyzing 7 sets of proteomes.
• Included a total of 15 species across these sets.
• Analyzed average proteome-wide identity within sets of three species.

Main Results:

• Confirmed the genetic equidistance result as a universal phenomenon across all 7 sets.
• Demonstrated that the least complex species is, on average, equidistant to two more complex species.
• Observed a consistent, albeit stepwise, increase in biological complexity during evolution.

Conclusions:

• The genetic equidistance result is a universal phenomenon reflecting maximum genetic distance, not a constant mutation rate.
• Evolutionary complexity increases in a stepwise manner, which is the true subject of the original molecular clock hypothesis.
• These findings provide further support for the maximum genetic diversity (MGD) hypothesis.