Chapter 13, Problem 8A

Summary Introduction

To infer:

The reason for non-existence of pure bred in the wild.

Introduction:

The process by which desired traits of certain plants and animals are selected and passed on to their future generations is called selective breeding. This can be achieved through hybridization and inbreeding. It increases the frequency of desired allele within a population.

Answer to Problem 8A

Inbreeding helps in maintaining pure breeds. Special care needs to be taken to inbreed the organism within its own group. This is not possible in the wild where organisms of one group often breed with organisms of other group. Pure breeding in the wild will result in homozygous recessive traits to be expressed which might prove to be detrimental.

Explanation of Solution

Pure breeds can be maintained by inbreeding as it results in offspring that are homozygous for most traits. Augus cattle and German shepherd dogs are examples of organisms produced by inbreeding. Special care is taken so that the animals don’t breed outside their group. It is very difficult for animals to breed within their group in nature.

Inbreeding increases the chances of homozygous recessive offspring. So if both parents carry the recessive allele, the harmful trait will not get eliminated and will be expressed in future generations. So if inbreeding occurs in the wild, many animals may die due to homozygosity for some lethal traits.

Hence pure bred animals don’t exist in nature.