Chapter 15.3, Problem 2MI

Summary Introduction

To define:

The given word “allele” using a book or a dictionary.

Introduction:

Although Darwin’s theory of natural selection remains the central dogma of evolution, population genetics and molecular biology have led to the development of evolutionary theory. Evolution occurs at population level with genes as the raw material.

Answer to Problem 2MI

Alternate form of a character trait that can be inherited is called an allele.

Explanation of Solution

Before twentieth century scientists were unaware about genes but alleles were understood to be one or more forms of an inherited character trait such as color of eye that is inherited from parent to offspring. Dominant alleles overpower the recessive alleles in a population.

Hardy and Weinberg showed mathematically that evolution will not occur in a population unless allelic frequencies are acted upon by forces that cause change. When these forces are absent, the allelic frequencies remain the same and evolution does not occur. This idea came to be known as the Hardy- Weinberg principle.

According to the Hardy- Weinberg principle, when the allelic frequencies remain constant the population is in genetic equilibrium.