Multiple Alleles & X-linked traits Flashcards
Part of Mandellian Gentics
What are multiple alleles?
Multiple alleles are when a certain trait has more then one allele.
Example of multiple alleles.
Blood type. Think of the AB blood type and tie it back to co-dominance. It’s genotype is ‘I^AI^B’. remember, ‘i’ is recessive and if the genotype is ‘ii’, the person has ‘O’ type blood.
Why can’t certain blood types accept different blood types (ex. A and B)?
One word. Proteins. Any blood type (except for O) has certain protein markers outside their cell membrane. This marker acts like a checkpoint.
If the new ‘A’ blood matches with the data at the checkpoint, it will be accepted, but if an incoming ‘B’ blood type gets to the checkpoint for ‘A’ type blood, it will get rejected by the bodies immune system because it is unrecognized and seen as a threat.
Quick pointer on transfusions.
AB blood types can receive blood from anyone because of the proteins it possess. ‘O’ type blood can donate to any type of blood due to it’s lack of protein.
What are X-linked traits?
X-linked traits are when different recessive disorder traits occur on the ‘X’ chromosome. Because the trait is recessive, they tend to appear more for men then women (the extra ‘X’ for women act as a backup whilst men do not have that luxury).
Women have that extra X. So?
Just because they have it doesn’t mean it’s not there. If it only occurs on one chromosome instead of both, it means they are a carrier and if they have a beautiful baby potato one day (that’s a guy), that recessive trait has a higher chance of being passed on to them.
What is an example of one of these traits?
COLOR BLINDNESS!!! It is the best example of sex-linked traits that a person could give.
