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Genetic Diversity
DNA determines the considerable variety of proteins that make up each organism.

Therefore similarities and differences between organisms may be defined in terms of
variation in DNA.

Gene - a section of DNA that codes for one or more polypeptides.

Genetic Diversity Within a Species Genetic Diversity Within…

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Factors Influencing Genetic Diversity

Selective Breeding
Selective breeding is known as 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 at least prevented from

In this way allele for…

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The Founder Effect

The founder effect occurs when just a few individuals from a population colonise a new

These few individuals will carry with them only a small fraction of the alleles of the
population as a whole.

These alleles may not be representative of the larger population from…

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Genetic Bottlenecks
A genetic bottleneck is an event that causes a big reduction in a population.

Sometimes the reason for this drop is a chance event, such as a volcanic eruption or
interface by man.

The few survivors will possess a much smaller variety of alleles than the original population.…

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Ethics of Selective Breeding in Domesticated

Almost all scientific progress has both benefits and risks.

Scientists carry out research into various techniques of selective breeding from which they
can report on the benefits and risks of each.

Interested parties, such as government agencies, farmers, food producers, supermarkets
and shopkeepers,…

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Ethical Implications
Is selective breeding interfering with nature?

Do other species have rights?
Should the development of new varieties be allowed to take place naturally, as it has
successfully done for millions of years?
Do domesticated animals have value in themselves or only in terms of usefulness to

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Selective Breeding in Cattle
The breeding of farm animals, such as cattle, has never been a random affair.

Farmers have chosen the most suitable domesticated animals and plants to parent the next

Selective breeding is therefore not new but traditional forms of selective breeding are slow
and imprecise.



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