9. Genetic Diversity Flashcards
What section of DNA codes for one or more polypeptides?
A gene
What leads to genetic diversity?
Differences in DNA
Organisms differ in their……… Not their ……..
Organisms differ in their alleles, not their genes.
What increases the genetic diversity of a species?
The greater the number of different alleles that all members of the species possess, the greater the genetic diversity.
Increased genetic diversity results in…
The increased likelihood that the species will be able to adapt to some environmental change. There is greater probability that some individual will possess a characteristic that suits it to the new environmental conditions.
What is selective breeding also known as?
Artificial selection.
What is artificial selection?
It involves identifying individuals with the desired characteristics and using them to parent the next generation. Offspring that do not exhibit the desired characteristics are killed or prevented from breeding. Alleles for unwanted characteristics are bred out of the population.
What does selective breeding lead to?
A population which all possess the desired qualities but which has reduced genetic diversity.
Why is selective breeding carried out?
To produce high yielding breeds of domesticated animal/strains of plants.
What is the founder effect?
The founder effect occurs when just a few individuals from a population colonise a new region - they carry with them only a small fraction of the alleles of the population as a whole. They are therefore less genetically diverse. This population is genetically distinct from the original population. The new population may in time develop into a separate species.
Describe the effects of genetic bottlenecks.
When a population is decreased dramatically due to climate or interference by man the number of alleles in the remaining population is significantly decreased. The genetic diversity will be less and will remain restricted even as the population grows.
What should be thought about when debating about selective breeding?
Scientific research requires funding - who funds the research may have an influence on its outcome.
Scientists are largely self-regulating. They may have different ethical codes, depending on religion, personal and moral beliefs.
The selective breeding of domesticated animals raises some issues:
Is selective breeding interfering with nature?
Is it acceptable to select features because they are desirable to their owners?
Animal welfare issues
Causing less genetic diversity
Should we select eco animals?
Are we driven too much by consumerism?
Genetic engineering/adopting traditional methods?
What method has been used to increase the pace of selective breeding?
Artificial insemination
Why would you selectively breed cattle?
For meat - Aberdeen Angus
High muscle to bone ratio
For milk - Holstein
High fat and protein content
Udder suits milking machine
