Why should mitochondria define species?

Stoeckle M.Y.
Program for the Human Environment
The Rockefeller University
1230 York AVE
New York, NY 10065
USA
Email: mark.stoeckle@rockefeller.edu

Thaler D.S.
Biozentrum, University of Basel
Klingelbergstrasse 50/70
CH - 4056 Basel
Switzerland
Email: david.thaler@unibas.ch
davidsthaler@gmail.com

HUMAN EVOLUTION Vol. 33 - n. 1-2 (1-30) - 2018

DOI: 10.14673/HE2018121037

Why should mitochondria define species?
Key words: Species evolution,
mitocondrial evolution, speciation,
human evolution.

HUMAN EVOLUTION Vol. 33 - n. 1-2 (1-30) - 2018

More than a decade of DNA barcoding encompassing
about five million specimens covering 100,000 animal
species supports the generalization that mitochondrial
DNA clusters largely overlap with species as defined by
domain experts. Most barcode clustering reflects synonymous substitutions. What evolutionary mechanisms account for synonymous clusters being largely coincident
with species? The answer depends on whether variants
are phenotypically neutral. To the degree that variants are
selectable, purifying selection limits variation within species and neighboring species may have distinct adaptive
peaks. Phenotypically neutral variants are only subject
to demographic processes—drift, lineage sorting, genetic
hitchhiking, and bottlenecks. The evolution of modern
humans has been studied from several disciplines with
detail unique among animal species. Mitochondrial barcodes provide a commensurable way to compare modern
humans to other animal species. Barcode variation in the
modern human population is quantitatively similar to that
within other animal species. Several convergent lines of
evidence show that mitochondrial diversity in modern
humans follows from sequence uniformity followed by
the accumulation of largely neutral diversity during a
population expansion that began approximately 100,000
years ago. A straightforward hypothesis is that the extant
populations of almost all animal species have arrived at
a similar result consequent to a similar process of expansion from mitochondrial uniformity within the last one to
several hundred thousand years.

 полный текст статьи -  Stockle_Thaler