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Jean M
10-29-2015, 11:58 AM
Michelle Alexander, Simon Y. W. Ho, Martyna Molak, Ross Barnett, Örjan Carlborg, Ben Dorshorst, Christa Honaker, Francois Besnier, Per Wahlberg, Keith Dobney, Paul Siegel, Leif Andersson and Greger Larson, Mitogenomic analysis of a 50-generation chicken pedigree reveals a rapid rate of mitochondrial evolution and evidence for paternal mtDNA inheritance, Biology Letters, 11: 20150561.
http://rsbl.royalsocietypublishing.org/content/11/10/20150561


Mitochondrial genomes represent a valuable source of data for evolutionary research, but studies of their short-term evolution have typically been limited to invertebrates, humans and laboratory organisms. Here we present a detailed study of 12 mitochondrial genomes that span a total of 385 transmissions in a well-documented 50-generation pedigree in which two lineages of chickens were selected for low and high juvenile body weight. These data allowed us to test the hypothesis of time-dependent evolutionary rates and the assumption of strict maternal mitochondrial transmission, and to investigate the role of mitochondrial mutations in determining phenotype. The identification of a non-synonymous mutation in ND4L and a synonymous mutation in CYTB, both novel mutations in Gallus, allowed us to estimate a molecular rate of 3.13 × 10−7 mutations/site/year (95% confidence interval 3.75 × 10−8–1.12 × 10−6). This is substantially higher than avian rate estimates based upon fossil calibrations. Ascertaining which of the two novel mutations was present in an additional 49 individuals also revealed an instance of paternal inheritance of mtDNA. Lastly, an association analysis demonstrated that neither of the point mutations was strongly associated with the phenotypic differences between the two selection lines. Together, these observations reveal the highly dynamic nature of mitochondrial evolution over short time periods.

Also covered here:
http://www.sci-news.com/biology/science-mitochondrial-evolution-mtdna-chickens-03387.html
Mitochondrial Evolution Can Happen Much Faster Than Thought, New Study Reveals


A new study published this week in the journal Biology Letters overturns the popular assumption that the mitochondrial evolution is only visible over long time scales.

http://www.sciencedaily.com/releases/2015/10/151027213417.htm
Chicken study reveals evolution can happen much faster than thought


Scientists found two mutations that had occurred in the mitochondrial genomes of the birds in only 50 years, showing a rate of evolution much higher than the widely accepted rate of change in the mitochondrial genome of about 2 percent per million years.

Source: Oxford University press release:
http://www.ox.ac.uk/news/2015-10-28-chicken-study-reveals-evolution-can-happen-much-faster-thought-0
Chicken study reveals evolution can happen much faster than thought