Quote Originally Posted by Dorsetman View Post
...
This business about mitochondria being responsible for basic functions, and only descending through the mother line is true of all life as far as I know ; certainly true of homo sapiens (us ) - and from my reading we are all descended ( or maybe its "only" just all white caucasian types) from just a handful - actually about 20, females, all those generations ago at the beginning of our species. On that basis 5% of the population are cousins. Mind blowing !
With animals I think it is 99.5% of our dna in the nucleus and coming from both parents , and ½ of 1% from the mitochondria from the mother . Now in flowers, it is I think 95% from the nucleus and both parents, 4.5% from the chloroplasts and the same 1/2 of 1% from the mitochondria . The chloroplast dna is also passed down the mother, i.e. pod parent line , and the nuclear dna from both pod and pollen parents. Much of the flower structure and colour comes from the genes in the chloroplasts - whiuch indicates the importance of making a hybrid cross one particular way, i.e. with the two parents together, choosing which will carry the pod.
At least some conifers are an exception to the matrilineal inheritance of mitochondria, and many conifers (maybe most or all) get their chloroplasts through the pollen line. Life seems to have exceptions to every rule, and many species have not been studied in this way, so I doubt we know all the variations on this.

Estimates on the single female-line ancestor of all living humans based on mitochondrial studies puts her anywhere from about 100,000 to 250,000 years ago, so we're all cousins. (At the risk of setting off some 6000 year old Earth anti-evolution types.)

Quote Originally Posted by sciencegal View Post
I love mitochondria discussions. I was the main technician involved in the research many years ago that for the first time actually proved that mitochondria were inherited from the mother in mammals. It was assumed but never proven. I used rats that were thought to be perfectly genetically related. It was the time when recombinant DNA work just started and everyone was all concerned that we were going to be making Frankenstein monsters.. In some of the work I was doing with mitochondrial DNA it was discovered that the mitochondria in these lab rats were of two different types. This made it easy to breed the rats, extract their mitochondrial DNA and see how it was inherited. Those were the good ol' days.
Nice work Karin, but I may have you beat on the Frankenstein factor. At one time my job was in production of some of the first GMO crops, putting genes where they didn't belong. (Now I know I'm going to get some hate mail.)