Chapter 10.2, Problem 8MI

Compare genotypes and phenotypes for pea plants.

Summary Introduction

To compare:

Genotypes and phenotypes of pea plants by completing the given table

Introduction:

A cross that involves hybrids for a single trait is called a monohybrid cross. An organism with two of the same alleles for a particular trait is called homozygous while an organism with two different alleles for a particular trait is called heterozygous.

Answer to Problem 8MI

Genotype	Homozygous/ Heterozygous	Phenotype
YY	Homozygous	Yellow seeds
Yy	Heterozygous	Yellow seeds
yy	Homozygous	Green seeds

Explanation of Solution

The outward appearance of an organism does not always indicate which pair of alleles is present. The allele pairs in the organism are called genotype. The way an organism looks or behaves is called phenotype.

A dominant allele is denoted by a capital letter while a recessive allele is denoted by a lowercase letter. Y is used to denote allele for yellow seed and y is used to denote allele for green seed.

Phenotype of a yellow plant is yellow. Genotype of a yellow plant can be YY or Yy . If we know the genotype, we can predict the phenotype.

A homozygous yellow- seed plant can be represented as YY.

A heterozygous yellow- seed plant can be represented as Yy .

A green- seed plant can be represented as yy. (Since green is a recessive trait, it will be expressed only in homozygous condition.)