Mendelian Genetics Flashcards
What is incomplete dominance?
It is where neither allele is completely dominant over the other, and as a result, the resulting offspring exhibit a phenotype that is a mixture of both parent phenotypes.
What is co-dominance?
It is where both allele are fully expressed in the resulting offspring.
What will the ratio of F2 progeny be in incomplete dominance?
1:2:1
What is the relationship between the A, B and O alleles of the human ABO blood group?
A and B are codominant with respect to each other, but dominant over O.
What is the function of the FUT1 allele?
The allele directs the addition of fucose to the H substance precursor.
What is the function of Ia allele of the ABO gene?
The allele directs the addition of N-acetylgalactosmine to the H substance.
What is a the function of Ib allele of the ABO gene?
The allele directs the addition of galactose to the H substance.
What does the ABO gene encode for?
Glycosyltransferases.
What is Epistasis?
It is the phenomenon where the expression of one gene masks or modifies the expression of another gene.
How can the Bombay phenotype be an example of Epistasis?
Individuals with the Bombay phenotype have the fut1 gene (instead of FUT1) which prevents the synthesis of complete H substance. As a result, A and B antigen production is suppressed.
(The fut1 fut1 genotype is epistatic to Ia, Ib and IaIb)
What is the Bombay phenotype?
It is where no A or B antigens are produced on the individual’s red blood cells.
What is a novel Phenotype?
A novel phenotype is [the development] of a new unique phenotype.
How does the white Novel Phenotype arise in Drosophila?
It occurs when there is a mutation in both of the alleles involved in eye pigmentation are mutated. The mutation causes in no drosopterin or xanthommatin being synthesized, resulting in the affected offspring having white eyes.
