Most offspring resemble their parents in a number of characteristics, but there are often some characteristics in the offspring that are unexpected.
Explain, using examples, how genetics and the environment can affect the phenotype of individuals. (8 marks)
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→ Offspring inherit characteristics based off their parents. Their are various factors which can influence what characteristics, or phenotype, they actually exhibit.
→ When offspring exhibit characteristics that are unexpected, this is often due to the characteristic being a recessive trait. In this way, both parents had the allele for it but it was masked by the dominant trait. The offspring then inherited both of these recessive alleles, meaning it could no longer be masked.
→ One such example is if the parents are both type A but their son/daughter is type O as a result of inheriting the recessive allele for no surface proteins.
→ Traits can also be unexpected if they are sex-linked, meaning the allele lies on an X sex chromosome. In this way, males will only have to have one recessive X allele for it to be expressed, while females need them both. In this way, the ratios for sex-linked characteristics is different than if they were autosomal.
→ When genes are being copied, mistakes (mutations) are made in the process and new genes or combinations of genes can be generated in the process.
→ These can be passed on to offspring, giving them characteristics different from their parents. For example, the peppered moth. Dark coloured peppered moths appeared in the population due to a mutation.
→ The environment can affect the way in which genes are expressed so that an individuals phenotype is affect by environmental conditions. For example, malnutrition can lead to individuals being shorter in height compared to their genetic potential.
→ Offspring inherit characteristics based off their parents. Their are various factors which can influence what characteristics, or phenotype, they actually exhibit.
→ When offspring exhibit characteristics that are unexpected, this is often due to the characteristic being a recessive trait. In this way, both parents had the allele for it but it was masked by the dominant trait. The offspring then inherited both of these recessive alleles, meaning it could no longer be masked.
→ One such example is if the parents are both type A but their son/daughter is type O as a result of inheriting the recessive allele for no surface proteins.
→ Traits can also be unexpected if they are sex-linked, meaning the allele lies on an X sex chromosome. In this way, males will only have to have one recessive X allele for it to be expressed, while females need them both. In this way, the ratios for sex-linked characteristics is different than if they were autosomal.
→ When genes are being copied, mistakes (mutations) are made in the process and new genes or combinations of genes can be generated in the process.
→ These can be passed on to offspring, giving them characteristics different from their parents. For example, the peppered moth. Dark coloured peppered moths appeared in the population due to a mutation.
→ The environment can affect the way in which genes are expressed so that an individuals phenotype is affect by environmental conditions. For example, malnutrition can lead to individuals being shorter in height compared to their genetic potential.