The effect of mutations
- Created by: une-meduse
- Created on: 13-05-13 17:02
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- Mutations
- Neutral effects
- An allele is an alternative version of a gene, at the same locus and codes for the same polypeptide
- If a gene is altered by a change to its base sequence, it becomes an allele of the gene
- It may produce no change to the organism if:
- It is in a non coding region of the DNA
- It is a silent mutation
- It may produce no change to the organism if:
- If the mutatuon does cause a change to structure and therefore characteristic, but this gives no disadvantage or advantage then the effect is also neutral
- Free ear lobes v attached ear lobes - there appears to be no advantage
- Harmful effects
- Early humans in Africa almost certainly had dark skin
- The pigment melanin protected them, but they could still synthesise vitamin D as there was intense sunglight
- Anyone with a mutation for paler skin would most likely burn and suffer from skin cancer
- Moving to more temperate climates means that the sunlight was not intense enough for those with darker skin
- Humans with paler skin would have had an advantage in temperate climates, where their pale skin was a disadvantage in intense climates
- Early humans in Africa almost certainly had dark skin
- Beneficial effects
- Early humans in Africa almost certainly had dark skin
- The pigment melanin protected them, but they could still synthesise vitamin D as there was intense sunglight
- Anyone with a mutation for paler skin would most likely burn and suffer from skin cancer
- Moving to more temperate climates means that the sunlight was not intense enough for those with darker skin
- Humans with paler skin would have had an advantage in temperate climates, where their pale skin was a disadvantage in intense climates
- Early humans in Africa almost certainly had dark skin
- Neutral effects
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