Gene Interactions and Inheritance

10 Questions

What is the main difference between allelic and non-allelic gene interactions?

Allelic gene interactions occur between different forms of the same gene, whereas non-allelic gene interactions occur between genes on different chromosomes.

What did Bateson and Punnett's breeding experiments with chickens reveal?

Genes interact with each other to influence traits.

What type of gene interaction occurs when the presence of a dominant allele at one gene locus masks the effects of alleles at another locus?

Dominant epistasis

Which of the following is an example of a non-allelic gene interaction?

Complementary genes

What do gene interactions affect in an organism?

The expression of specific phenotypic traits

What is the effect of the dominant allele W on pigment synthesis in foxglove petals?

It restricts pigment synthesis to throat spots.

What type of epistasis occurs when the recessive allele of one gene locus masks the phenotype expression of alleles at another gene locus?

Recessive epistasis

What is the result of the interaction between the e allele and the B and b alleles in Labrador retriever dogs?

A yellow coat color

What is the effect of the alleles d and D on the petals of foxgloves?

They affect the red pigment intensity.

What is the term for the phenomenon where the effect of one gene is dependent on the presence of another gene?

Epistasis

Study Notes

Gene Interactions

Gene interactions refer to the relationships between genes that affect the phenotype of an organism.
Gene interactions occur when allelic or non-allelic genes affect the expression of specific phenotypic traits in an organism.

History of Gene Interactions

The study of gene interactions gained recognition following Gregor Mendel’s work on inheritance.
Unlike Mendel’s initial observations, it was discovered that inheritance is not a simple one-gene, one-trait relationship.
Gene interactions involve the interaction of multiple genes, and their combined effects cannot be predicted by studying them individually.

Early Evidence of Gene Interactions

Bateson and Punnett conducted breeding experiments with chickens, providing early evidence that traits can be influenced by multiple genes.
Their research showed that observed ratios of inherited traits did not always follow Mendelian patterns, indicating that genes interact with each other.

Types of Gene Interactions

Allelic gene interactions occur between different forms (alleles) of a single gene.
Non-allelic gene interactions refer to interactions between genes that are located on the same or different chromosomes but do not involve alleles of the same gene.

Allelic Gene Interactions

Complete dominance: one allele is completely dominant over another allele.
Incomplete dominance: the effect of one allele is not completely masked by the other allele.
Codominance: both alleles have an equal effect on the phenotype.
Lethal allele: an allele that causes the death of an organism.
Multiple alleles: a gene with more than two different alleles.

Non-Allelic Gene Interactions

Complementary genes: genes that work together to produce a single phenotype.
Epistasis: the interaction between two or more genes that affect a single phenotype.
Epistasis can be of two types:
- Dominant epistasis: the presence of a dominant allele at one gene locus masks the effects of alleles at another locus.
- Recessive epistasis: the recessive allele of one gene locus masks or prevents the phenotype expression of alleles at another gene locus.

Significance of Gene Interactions

Gene interactions are significant in understanding biological processes.
Studying gene interactions can provide valuable information about the interactions between genes and their effects on phenotypic traits.