dominance and recessiveness

[ntdna]

hi

i have a question "what are the molecular basis of dominance et recessiveness and What makes a gene recessive or dominant?"

 

[GeoffP]

Good question. Presumably the products of one allele or the other are metabolically more effective or more numerous (or less effective/numerous for recessive alleles) than those of their counterparts at the same locus. I have to admit, I've never actually looked it up, although I probably should and soon.

 

[ntdna]

thanks in advance

 

[ULTRA]

As in Mendelean genetics?

 

[Hercules Rockefeller]

i have a question "what are the molecular basis of dominance et recessiveness and What makes a gene recessive or dominant?"

The molecular/biochemical basis of a recessive allele is usually a loss of function (ie. a “null allele”). If you think about it, that’s really the only way a dominant-recessive relationship can occur. If one allele is merely ‘less efficient’ than another, you would get an additive/co-dominant/incomplete dominance relationship. This is the basis of the interactions of nearly every allele at every locus. In humans there are very few genuine dominant-recessive traits, ie. very few human traits display true Medelian inheritance.

 

[GeoffP]

The molecular/biochemical basis of a recessive allele is usually a loss of function (ie. a “null allele”). If you think about it, that’s really the only way a dominant-recessive relationship can occur. If one allele is merely ‘less efficient’ than another, you would get an additive/co-dominant/incomplete dominance relationship. This is the basis of the interactions of nearly every allele at every locus. In humans there are very few genuine dominant-recessive traits, ie. very few human traits display true Medelian inheritance.

My answer is necessarily quantitative, but you're right about loss-of-function mutations, naturally, which my fatigued mind forgot. I'm not much in for binaries generally though.

Incomplete dominance is king.