IUBio

Molecular Clocks & Generation Time

James Shotter james at hades.omen.com.au
Thu May 18 10:56:28 EST 1995


 c> around 7 million primordial oocytes. The oocytes then enter a prolonged
 c> dictyate resting stage and meiosis recommences at 
 c> ovulation to be completed
 c> (ie reach the haploid stage) after sperm entry.  
 c> Errors accumulate largely
 c> as chromosomal factors (eg Downs syndrome) By contrast, spermatogenesis
 c> starts at puberty and is continuous.  Thus a sperm 
 c> produced by a 50 year
 c> old man (do I give myself away here?) has been 
 c> through many more division
 c> cycles than the equivalent gamete in a female.    This leads to genetic
 c> errors primarily through DNA breakage and replication errors.
 
Ahhhhh, thankyou sir!
 
regards,
  james
 
(re: Murdoch University vet/anatomy prof reply; Perth, W.Oz.)




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