Module 8 Lesson 3 - 1

Get Focused

Why are population geneticists so concerned with allele frequencies and whether they are increasing or decreasing? In general, the more variation in a gene pool the better. A population with frequencies of 99% for dominant allele and only 1% for recessive allele is in a dangerous situation. If the environment were to change to favour the recessive allele, the amount of recessive alleles in the gene pool might be insufficient to produce enough survivors for the next generation. Low genetic diversity can result in extinction. 

Domesticated animals (livestock) have been bred to become genetically very similar. This has resulted in consistent meat quality and handling traits. However, the lack of diversity in their gene pool means that they are all susceptible to the same types of diseases. Similarly, animal populations kept isolated in wildlife reserves may suffer the same problem. They can become so genetically similar that they are all susceptible to the same environmental assaults - whether in the form of disease or climate change.

Are changes in gene pools positive or negative? What kinds of conditions produce high biodiversity and what conditions do not? In this lesson, you will learn about five methods by which these changes occur.

Human species have the ability to change their environment significantly, often with unintended consequences. However, technology has provided the means by which we can manage and preserve both wild and domestic populations more effectively and with more positive outcomes.

By the end of this lesson, you should be able to answer to these three focusing questions:

• What are the causes of change in a gene pool?

• What factors cause changes in diversity of the composition of a gene pool?

• What are the intended and unintended consequences of human scientific and technological developments on gene pools?