Genetic Revolutions

CL Notes for a discussion in relation to an SB lecture about Mitochondrial DNA

Archaeogenetics deserves a better name as evolutionary studies based on retro-interpretation from the living replace “ancient-DNA”, fraught with difficulties, as data. Mitochondrial DNA is a single-stranded ring now nearly all sequenced comprising 37 genes and non-coding hyper-variable segments including repeats. There are multiple mitochondria per egg cell assumed to be all genetically alike. Thus only maternal inheritance is supposed despite sperm containing a mitochondrion to power it, whose contribution to inheritance is the embryo is discounted. Early studies based on the hypervariable region of MtDNA are now being greatly extended in depth and precision by being able to use markers over the entire Mt genome. The long-standing problems attending the human habitation of the Pacific are now being re-addressed. Opposing views continue but may be resolvable. Eastern Indonesia now appears to be one of several distributional bottlenecks and at least two major episodes of Pacific colonization. One of these is the long coastal route through Arabia and Western Malaysia from Africa. Now, increasingly, Y-chromosome, hence entirely male-specific, studies and studies from markers on the total genome are also being used to illuminate history and interpret pre-history of humanity. Studies of human migration also interact with concerns over global warming and studies of past climate change and the changes to the geography of land and sea.