We, the human population is not selfish and independent.. There is a whole bigger mechanism tat ensures the survival of our species...
Antigen Presenting Cells have MHC molecules on them.. There are 3 classes of MHC molecules.. Class 1, 2 and 3...
For MHC Class 2, 6 different alleles for the molecule.. 3 alleles are inherritated from your mum and 3 frm your dad..
MHC molecules present antigens to lymphocytes so that hopefully, one randomly synthesised lymphocyte in the primary lymphoid tissue will recognise the 3D structure of the antigen and binds to it.. This lymphocytes (T helper cells) then singal B cells to produce anitbodies so tat we can be protected...
There are millions n millions n millions of different alleles.. So the probabilty of finding 2 individuals having the same 6 alleles is very very low.. This ensures tat if a disease strike, some of us will survive.. OOoo.. So humans wont go extinct..
Know why we cant marry our close family members or relatives?This is coz if we do so, the number of alleles we have will be lower than 6.. and this decreases our immunity greatly.. So we are more subceptible to infections n diseases.. So lots of problems n no good..
Who do we like and how do we choose our other half?Studies have also shown that we prefer the smell of the opposite sex who have different alleles from us.. This ensures tat we have all 6 different kinds of alleles and not of the similar or same kind.. So that our immunity would be maximised. However, women on contraceptive pills will prefer smell of the opposite sex who have similar alleles as them..
SO BEWARE IF U ARE ON PILLS... one day when u decided to start a family, and stop taking the pills, u may start to hate your husband.. and thinks he smells like the rubbish bin.. hehehe.. How then do mice distinguish and prevent mating from close relatives? Mice prefer to mate with other mice who have different MHC alleles as compared to them.. and they distingush this by the smell of the other mice urine..
