The question asks for the term describing alternative forms of a gene found at the same location on homologous chromosomes. This is a fundamental concept in genetics.
Correct Option: A) Alleles are alternative forms of a gene that occupy the same locus on homologous chromosomes. They determine the variations in a particular trait.
The question asks for the term that describes the observable physical or biochemical characteristics of an organism. This is a fundamental concept in genetics and biology.
C) Phenotype — The phenotype refers to the observable physical or biochemical characteristics of an organism, which result from the interaction of its genotype with the environment. Examples include eye color, height, blood type, and disease susceptibility.
This question tests basic genetic terminology. It asks for the term used to describe an individual with two identical alleles for a specific trait. Understanding the definitions of key genetic terms like homozygous, heterozygous, hemizygous, and nullizygous is crucial.
C) Homozygous. An individual is homozygous for a trait if they have two identical alleles for that trait. For example, an individual with genotype TT is homozygous dominant, and an individual with genotype tt is homozygous recessive.
The question asks to identify the organism that best illustrates incomplete dominance in flower colour inheritance. Incomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not completely expressed over the other allele. This results in a third phenotype that is a blend of the parental phenotypes.
Correct Option: B) Mirabilis jalapa (Four o'clock plant)
In Mirabilis jalapa, when a homozygous red-flowered plant (\(RR\)) is crossed with a homozygous white-flowered plant (\(WW\)), the \(F_1\) generation consists entirely of pink-flowered plants (\(RW\)). This pink colour is an intermediate phenotype, demonstrating incomplete dominance. If these \(F_1\) pink plants are self-pollinated, the \(F_2\) generation will show a phenotypic ratio of 1 Red: 2 Pink: 1 White, and a genotypic ratio of 1 \(RR\): 2 \(RW\): 1 \(WW\).
The question asks for the F2 phenotypic ratio in a monohybrid cross exhibiting incomplete dominance. We need to recall the principles of incomplete dominance and how it differs from complete dominance in terms of phenotypic expression.
| R | W | |
|---|---|---|
| R | RR | RW |
| W | RW | WW |
C) 1 : 2 : 1. This ratio correctly represents the phenotypic outcome in the F2 generation of a monohybrid cross under incomplete dominance, where the heterozygous genotype expresses an intermediate phenotype.
The question asks to identify the genetic phenomenon where both alleles in a heterozygous individual express themselves fully and independently. We need to evaluate each option based on its definition in genetics.
A) Codominance is the phenomenon where both alleles of a heterozygous individual express themselves fully and independently. This means that both traits associated with the alleles are observable in the phenotype, without one masking the other or blending to form an intermediate.