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Mutations

_ishita_

Why are mutations recessive? Is recessive a more appropriate answer to incompletely dominant?

Reply 1

games211

Original post by _ishita_

Why are mutations recessive? Is recessive a more appropriate answer to incompletely dominant?

Hey. For a recessive mutation to give rise to an abnormal phenotype, both alleles must carry the mutation. Is this what you were looking for? If only one allele is affected and it gives rise an abnormal phenotype- It's dominant.

(edited 6 years ago)

Reply 2

Dinasaurus

Who said mutations were recessive?

Reply 3

username2769500

Because the genotype is new! But it shouldn't be it probably is the various forms of dominant.

Reply 4

QuentinM

Universities Forum Helper

Original post by _ishita_

Why are mutations recessive? Is recessive a more appropriate answer to incompletely dominant?

Not all mutations are recessive! In several diseases, thankfully they are-like cystic fibrosis. i say "thankfully" because it makes the disease less common and more difficult to spread.

Some diseases-take Huntington's disease-are dominant disorders. Thankfully most of the cases are known in each country and are carefully managed to ensure they reduce the chance of having children with it.

And this is just a disease context...im sure someone could give you phenotypic, non pathogenic characteristics caused by dominant mutations.

Recessive inheritance and incomplete dominance are very different things. You may be familiar with co-dominance in inheritance....there are two types of rose plant, if i remember right, that are white and red-when you breed them, they make pink flowers. This is because the colour determining alleles (white and red) don't dominate each other, so an "intermediate" phenotype is made-in this case, pink.

Incomplete dominance is more similar to that. Its when this kinda happens, but one of these alleles is slightly more dominant in determining the phenotype. In this example....you'd probably see this as really faint pink flowers (if white had incomplete dominance over red) or flowers that were slightly less red than red roses (if red has incomlete dominance over white).

In the whole dominant-recessive scheme of things.....if an allele is recessive, it has an allele that is COMPLETELY dominant over it.