Ok I have to ask because this is driving me nuts.
Ok... So there are dominant and recessive genes. Typically recessive genes only manifest if coupled by other recessive genes.
Yet... it is possible for recessive genes to manifest in some way even if coupled with a dominant gene?
Just manifest in anyway.
Depends.
For the most part, they cannot by definition. If they did, they wouldn't be recessive relative to the other gene.
Devil's in the details though. You see, recessiveness is not a property of the gene; there isn't anything in the gene that says 'this be recessive'.
The dominant genes simply encode something that has an overriding function. For example, if one allele produces an enzyme with activity of 1 unit, and the other of 100 units in equal amounts, the latter will be dominant, because of all the enzyme in the cell, you won't notice the weak activity of the recessive gene's product. Mind you, transcription doesn't care, you have a 50-50 chance for which copy of the gene is being worked with.
Or, on the flipside, with dominant-inherited disorders, a mutation may lead to a protein that not only doesn't work, but actively prevents the healthy proteins from working as intended. For example the mutated, 'dead-end' filaments binding to normal ones - not only they cannot perform the job in itself, if a single mutant protein binds in one place, the whole multi-protein structure stops working, even if 99.9% of it is composed of the healthy form.
So both kinds of proteins are made in heterozygotes, which can have functional effects. A classical example is sickle cell anemia; if you have a single (recessive) copy of the anemia-causing variant, you do have the benefit of increased resistance to malaria compared to people with two healthy copies.
Author
Topic: The small random questions thread [WAAAAAAAAAAluigi] (Read 686880 times)