inheritance 1 Flashcards
- What is meant by the term phenotype?
The phenotype is the expression of this genetic constitution and its interaction with the environment.
- What is epistasis?
When two genes interact to control one characteristic/ when one gene controls the expression of another.
- What does it mean when two genes are linked? (autosomal linkage)
The two genes have loci on the same chromosome.
- What is meant by codominant alleles?
both alleles are expressed in the phenotype.
- What is meant by sex-linkage?
The gene has a loci on the X chromosome, but not on the Y chromosome (so males only have one copy of the gene).
- Why are recessive sex-linked characteristics more common in males (XY) than females (XX)?
Recessive allele is always expressed in the male (XY) as they only have 1 allele. Females need 2 recessive alleles as they are (XX).
- Explain what is meant by the dominant allele.
The allele that is always expressed in the phenotype.
- Explain the evidence that shows the (?) allele is recessive.
There are two parents (? And ?) that do not display recessive characteristic but have an offspring that does display recessive characteristic. Therefore, parents must be heterozygous.
- What is meant by a recessive allele?
The allele that is only expressed when there are 2 copies in the genotype.
- What are multiple alleles?
When there are more than 2 different alleles for a certain gene. An example would be blood alleles A,B and O.
- What is homozygous?
An organism with 2 of the same alleles for a particular gene.
- What is heterozygous?
An organism with 2 different alleles for a particular gene.
