Inheritance Flashcards
What is Homozygous?
A pair of homologous chromosomes carrying the same alleles for a single gene.
What is heterozygous?
A pair of homologous chromosomes carrying two different alleles for a single gene.
What is a recessive allele?
An allele only expressed if no dominant allele is present.
What is a dominant allele?
An allele that will always be expressed in the phenotype.
What is meant by codominance?
Where the heterozygous genotype has an intermediate phenotype, and both alleles are equally dominant
What is sex-linkage?
A gene whose locus is on the X chromosome
What is autosomal linkage?
Genes that are located on the same chromosome (but not the sex chromosomes)
What is Epistasis?
When one gene modifies or masks the expression of a different gene at a different locus.
How do you express codominant genotypes?
Gene^Allele + Gene ^Allele
Eg I^B I^O
What is the equation for allele frequency? (Hardy-Weinburg)
P + Q = 1
What is the equation for genotype frequency? (Hardy-Weinburg)
P^2 + 2PQ + Q^2 = 1
What is the typical ratio in autosomal linkage?
Although there are 2 different genes (similar to dihybrid) it is typically 3:1 in eg RrYy
