Question
Question: What type of inheritance controls blood types in humans?...
What type of inheritance controls blood types in humans?
Solution
The passing on of traits from parents to their offspring is known as heredity, also known as inheritance or biological inheritance. The offspring cells or organisms acquire the genetic information of their parents through asexual or sexual reproduction.
Complete answer:
The majority of blood group genes have a co-dominant pattern. A and B genes are co-dominant in the ABO system; C and c are co-dominant in the Rh system, and K and k are co-dominant in the Kell system. The capital and lowercase letters do not denote dominant and recessive alleles, as they do in classical genetics. Le and le, as well as H and h, are examples of dominant or recessive gene pairs. Almost all blood group genes are inherited on the autosomes.
Both parents' blood groups are passed down to their children. The gene I, which has three types of alleles,IA,IB, and icontrols blood group inheritance. From their parents, each person inherits a pair of alleles. Over i, IAandIB are dominant. When a pair of the same alleles are present, allele i results in O blood type (homozygous recessive).
When IA is present i in a heterozygous condition, allele A is expressed. Allele B is expressed when both IB and iare present, but when both IA and IB are present, both are expressed, and the blood group type is AB.
Genotype | Blood Type |
---|---|
IAIA | A |
IAIB | AB |
IAi | A |
IBIB | B |
IBi | B |
i$$$$i | O |
Note:
Many antigens of the blood groups are indirect gene products. Antigens A and B, for example, are carbohydrates. Their genes produce transferases, which are proteins (enzymes) that transfer sugars from carrier to acceptor molecules. Antigen specificities are then stored in the added terminal sugars. Because genes can only produce proteins directly, these antigens must be produced indirectly. Usually, if a gene is present, its corresponding antigen will be present.