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Island in Micronesia ­
Pingelap…read more

Slide 2

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The Founder Effect
1775: storm ravaged island and killed 90% of the population
20 survived to replenish the isolated island's population
Nahnmwarki Mwanenised, the survivor, carried a single copy of a
mutant gene that became common
Some level of inbreeding was inevitable to repopulate the island
Relatives show many of the same alleles inherited from their
common incestor, there is a high probability that the offspring of
the two related parents would inherit an identical allele from
each parent
Result=increased recessive gene frequency…read more

Slide 3

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Of the population today, 5-10% are directly affected and
30% are carriers due to the small gene pool and rapid
population growth
After 4 generations (two second-cousin breeding),
citizens started exhibiting symptoms of the hereditary
disease where 2.7% were affected
Incident rose to 4.92% after 6 generations…read more

Slide 4

Slide 5

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Rare autosomal recessive sight disorder: achromatopsia
Complete inability to distinguish between colours
Little or no function of the cone cells
Persons with achromatopsia are only able to perceive
black, white and shades of gray; no real understanding of
the concept of color…read more

Slide 6

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Both parents contribute to a gene in order for the condition to
Offspring may carry one gene for achromatopsia
In order to pass the condition onto their children, it would
require having children with someone else carrying the same
gene and passing a gene from each parent
This case highlights the necessity of genetic variation to
ensure that genetic mutations are suppressed through the
natural selection process.…read more

Slide 7

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