Steve Hayes <hayesmstw@hotmail.com> wrote: >If this goes any further, we may need genealogy software that allows one to >enter three or more parents - and what would a pedigree chart look like then? > >http://news.yahoo.com/s/ap/20080205/ap_on_sc/embryo_research > >LONDON - British scientists say they have created human embryos containing DNA >from two women and a man in a procedure that researchers hope might be used >one day to produce embryos free of inherited diseases. >ADVERTISEMENT > >Though the preliminary research has raised concerns about the possibility of >genetically modified babies, the scientists say that the embryos are still >only primarily the product of one man and one woman. There might be four (or more). There might have been a surrogate mother, and there is some evidence that genetic development is controlled in the womb in part by the maternal hormonal environment. The genes we are born with are not exactly the same as the ones in the fertilized egg, so that a surrogate mother is arguably part of one's genetic ancestry. lojbab

Bob LeChevalier wrote: > Steve Hayes <hayesmstw@hotmail.com> wrote: >> If this goes any further, we may need genealogy software that allows one to >> enter three or more parents - and what would a pedigree chart look like then? >> >> http://news.yahoo.com/s/ap/20080205/ap_on_sc/embryo_research >> >> LONDON - British scientists say they have created human embryos containing DNA >>from two women and a man in a procedure that researchers hope might be used >> one day to produce embryos free of inherited diseases. >> ADVERTISEMENT >> >> Though the preliminary research has raised concerns about the possibility of >> genetically modified babies, the scientists say that the embryos are still >> only primarily the product of one man and one woman. > > There might be four (or more). There might have been a surrogate > mother, and there is some evidence that genetic development is > controlled in the womb in part by the maternal hormonal environment. > The genes we are born with are not exactly the same as the ones in the > fertilized egg, so that a surrogate mother is arguably part of one's > genetic ancestry. Strictly speaking, the DNA we are born with is precisely the set of chromosomes that were in the fertilised egg (23 from father, 23 from mother), plus the mitochondrial DNA, which comes from mother. However, the expression of the genes in the DNA is controlled by a number of complex factors. By "expression", I mean which genes are active. Biologists are still trying to understand how gene expression is controlled, particularly for those genes which we get in two copies, one from each parent. In some cases, it's always the paternal copy which is active, and in others, it's always the maternal copy. This book is a very good introduction to some of the issues involved: http://www.amazon.com/X-Sex-Chromosome-Controls-Lives/dp/0674016211/ David Harper Cambridge, England