A paper published in PNAS a few weeks ago -Nov. 26. 2018- (1), reports that mtDNA from both mother and father has been found in seventeen individuals.
This is a very important finding because until now, mtDNA in humans, was assumed to be inherited on a matrilineal basis: the mother's mtDNA was passed on to the nesxt generation.
This type of inheritance was the origin of the Out of Africa theory, by which all extant humans can trace their mtDNA to a woman living in Africa some 200,000 years ago.
And the splits between different human groups are all branches marked by different mutations of the original mtDNA lineage.
If the father's mtDNA can find its way into his offspring, this will alter the matrilineal inheritance and impact on the timescales used to estimate the origin of mankind.
This is what the paper says (abstract) -the rest is behind a paywall:
"Significance
The energy-producing organelle mitochondrion contains its own compact genome, which is separate from the nuclear genome. In nearly all mammals, this mitochondrial genome is inherited exclusively from the mother, and transmission of paternal mitochondria or mitochondrial DNA (mtDNA) has not been convincingly demonstrated in humans. In this paper, we have uncovered multiple instances of biparental inheritance of mtDNA spanning three unrelated multiple generation families, a result confirmed by independent sequencing across multiple unrelated laboratories with different methodologies. Surprisingly, this pattern of inheritance appears to be determined in an autosomal dominantlike manner. This paper profoundly alters a widespread belief about mitochondrial inheritance and potentially opens a novel field in mitochondrial medicine.
Abstract
Although there has been considerable debate about whether paternal mitochondrial DNA (mtDNA) transmission may coexist with maternal transmission of mtDNA, it is generally believed that mitochondria and mtDNA are exclusively maternally inherited in humans. Here, we identified three unrelated multigeneration families with a high level of mtDNA heteroplasmy (ranging from 24 to 76%) in a total of 17 individuals. Heteroplasmy of mtDNA was independently examined by high-depth whole mtDNA sequencing analysis in our research laboratory and in two Clinical Laboratory Improvement Amendments and College of American Pathologists-accredited laboratories using multiple approaches. A comprehensive exploration of mtDNA segregation in these families shows biparental mtDNA transmission with an autosomal dominantlike inheritance mode. Our results suggest that, although the central dogma of maternal inheritance of mtDNA remains valid, there are some exceptional cases where paternal mtDNA could be passed to the offspring. Elucidating the molecular mechanism for this unusual mode of inheritance will provide new insights into how mtDNA is passed on from parent to offspring and may even lead to the development of new avenues for the therapeutic treatment for pathogenic mtDNA transmission."
This had been reported back in 2002 (2) (see paper), this new study confirms the original finding.
Sources
(1) Biparental Inheritance of Mitochondrial DNA in Humans
Shiyu Luo, C. Alexander Valencia, Jinglan Zhang, Ni-Chung Lee, Jesse Slone, Baoheng Gui, Xinjian Wang, Zhuo Li, Sarah Dell, Jenice Brown, Stella Maris
hen, Yin-Hsiu Chien, Wuh-Liang Hwu, Pi-Chuan Fan, Lee-Jun Wong, Paldeep S. Atwal, Taosheng Huang
Proceedings of the National Academy of Sciences Nov 2018, 201810946; DOI: 10.1073/pnas.1810946115
Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2014 by Austin Whittall ©
No comments:
Post a Comment