Question

Select the term indicating that the phenotypic effects of alleles for one gene can be suppressed by the alleles of another, independently inherited gene. a. phenotypic variation b. codominance c. gene-environment interaction d. epistasis

Short answer

d. epistasis

Step-by-step solution

Identify the Keywords

Focus on the key point of the question: 'phenotypic effects of alleles for one gene can be suppressed by the alleles of another, independently inherited gene'. This implies that the relationship between the alleles of two different genes affects the phenotype.

Understand Each Term

Review what each option means:- Phenotypic variation: Differences in appearance or function that are passed from one generation to the next.- Codominance: A situation where both alleles in a gene pair are fully expressed, resulting in a phenotype that is neither dominant nor recessive.- Gene-environment interaction: The effect of the interplay between genes and environmental factors on phenotypic results.- Epistasis: The interaction between genes where the effect of one gene is modified or suppressed by one or several other genes.

Match the Description

Determine which term best matches the description of one gene's alleles suppressing the phenotypic effects of another gene's alleles. This describes epistasis, where one gene can mask or modify the expression of another gene.

Select the Correct Answer

Based on the matching description, the correct term is 'epistasis'.

Key concepts

Gene Interaction

Gene interaction is a fundamental concept in genetics. It occurs when the effects of one gene are influenced by one or more other genes. This is also known as the interplay between different genes. Geneticists study these interactions to understand how complex traits and phenotypes arise.
There are several types of gene interactions, including:

• Epistasis: One gene masks or modifies the effects of another.
• Complementary Genes: Two or more genes collaborate to produce a phenotype.
• Modifier Genes: Genes that alter the effects of other genes.

Understanding gene interaction helps explain why genetic traits are not always inherited in a simple Mendelian fashion.
Instead, multiple genes can contribute to a single trait, making prediction and mapping more complex.

Phenotypic Suppression

Phenotypic suppression, commonly associated with epistasis, refers to situations where the presence of specific alleles at one genetic locus can counteract the expected phenotypic expression of alleles at another locus. This type of interaction reveals that the phenotype resulting from one gene can be masked or altered by the presence of alleles from a different, independently inherited gene.
In practical terms, phenotypic suppression can take various forms:

• Recessive Epistasis: When the recessive allele of one gene suppresses the expression of alleles of another gene.
• Dominant Epistasis: When a dominant allele of one gene suppresses the effects of another gene.
• Duplicate Genes: Two genes can compensate for each other, making certain phenotypic traits robust to mutations.

Recognizing phenotypic suppression is crucial for geneticists working to understand the underlying causes of various traits and diseases.

Independent Inheritance

Independent inheritance refers to the principle that genes located on different chromosomes are inherited separately from each other. This concept, first described by Gregor Mendel as the Law of Independent Assortment, is a cornerstone of classical genetics.
Here’s what you need to know:

• Independent Assortment: During meiosis, alleles of different genes distribute independently into gametes.
• Genetic Variation: Independent inheritance contributes to the genetic diversity in offspring.
• Genetic Mapping: Understanding independent inheritance helps in gene mapping techniques to locate genes on chromosomes.

While epistasis shows an interaction where one gene affects another, independent inheritance explains how genes on separate chromosomes can assort without influencing each other, leading to varied phenotypic outcomes in the offspring.