Re: marrying first cousins?
I don’t get it … I’ve done some calculations purely based on two factors:
Likely Pairings (Where I introduced my own indices)
Probablity of Expression (As is done with chromosomal pairings)
Generation 0
We have 4 (Aa)s - Aa is a Carrier (C), 4 (aa)s - aa is a recessive gene expressed (E) and 4 (AA)s i.e. non-carriers (N).
The possible pairings are:
(C,N), (C,C), (N,N), (E,N), (E,E), and finally (C,E)
Some of these are more likely than others to be paired in marriage. I took it as reasonable to set all pairings of carriers and non-carriers as equal to 30% each … and all pairings with expressed recessive genes totalling 10%, (E,N) and (C,E) would hence be 4% each, and an (E,E) pairing would be 2%.
As can be seen in the six pairings above, there are indeed 4Es, 4Cs, and 4Ns.
This gives a 1:1:1 - N:C:E ratio respectively.
In Generation 1, the ratio changes to this:
1.591 : 1.091 : 0.348
And then so on to the ratio of 5th Generation, which becomes this:
10.19 : 1.546 : 0.005
As can be seen the amount of carriers in 5 generations does increase by about 55% (1.546/1), however the Es drastically fall and tend towards elimination.
Conversely the pure Ns grow by over (1000%) (10.19/1)
**Unless there is another factor that suggests the recessiveness becomes dominant when handed down multiple carriers then the numbers suggest that recessive undesirable traits are eliminated even in the same gene pool … My conclusion is that “Carriers” merely pose the possibility of undesired expression, but the system is heavily geared against it …
**Besides this is all based on probability - It may well be that two married carriers have 4 children all of whom are in themselves non-carriers - this is quite possible given that two carriers (Aa,Aa) can have the following (AA, Aa, aA, aa) combinations. In my calculations I have assumed that each combination is equally weighted … but that weighting is an assumption the true weighting is really reliant ultimately on The Creator … not chance !!!