INHERITANCE AND HUMAN VARIATION
Causes:
ABO SYSTEM
It´s an example of qualitative trait.
They´re molecules in the membrane of red blood cells that act as antigens when they come ontact with the blood of another individual.
The antigen B is produced by IB.
The antigen i does not produces either A or B antigens.
RH SYSTEM
It´s a system based on the presence or absence of an antigen called the Rhesus (Rh) factor.
When a transfusion needed, the blood groups of the donor and the recipient must be compatible.
If the donor´s blood is incompatible whit the recipient´s blood, then the antibodies in the recipient´s blood react against the antigens in the donor´s blood.
People with tipe O are universal donors.
- Genetic differences: Genetic traits are inherited and make up the genotype of an individual.
- Enviromental factors: The effects that they produce they cannot be transmited to offspring.
- They have a range of possible expressions in phenotype.
- The difference between the expression is minimal
- Sometines they´re influed by enviromental factors.
- Many of this traits are determined by the cumulative effect of various pairs of genes.
- They usually have only a small number of alternative expressions: discrete, recognisable.
- They are only a little influed by enviromental factors.
- They are usually determined by a pair of alleles that are located on a single locus.
ABO SYSTEM
It´s an example of qualitative trait.
They´re molecules in the membrane of red blood cells that act as antigens when they come ontact with the blood of another individual.
- The A blood group: Antigen A. Its plasma produces anti-B antibodies.
- The B bloud group: Antigen B. Its plasma produces anti-A antibodies.
- The AB blood group: A and B antigens. Its plasma does not produce cither anti-B or anti-A antibodies.
- The O blood group: doesn´t have either of these antigens and its plasma produces both anti-A and anti-B antibodies.
- IA, IB and i
- IA = IB > i
The antigen B is produced by IB.
The antigen i does not produces either A or B antigens.
RH SYSTEM
It´s a system based on the presence or absence of an antigen called the Rhesus (Rh) factor.
- There are 2 blood groups, categorised according to their Rhesus factor : Rh +; Rh-.
- People whit Rh+ have an antigen on their red blood cells.
- people with Rh- don´t have this antigen.
- This is not a case of multiple allele inheritance.
When a transfusion needed, the blood groups of the donor and the recipient must be compatible.
If the donor´s blood is incompatible whit the recipient´s blood, then the antibodies in the recipient´s blood react against the antigens in the donor´s blood.
People with tipe O are universal donors.