Molecular Basis of genes - (Jan/02/2006 )

Hello

I need to know, that on the molecular level......what is it that makes a gene dominant or recessive? what factor decides if a gene is dominant or recessive?

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Hi!

What is rather dominant and recessive is the outcome of a gene, not the gene itself.

Mutations in dominant genes are very often of structural nature, that means you can easily detect them in the phenotype (thus it has a dominant outcome).

Mutations in recessice genes are more often found in genes of metabolism. If such a gene carries mutations the second allele may still produce the normal product (e.g. enzyme...) and thus you won´t find any obviuos phenotype.

So, it´s less the genes themselves that are dominant or recessice. It´s more related to the outcome that mutations in genes have and if you can detect them in the phenotype.

Cheers

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Hi...

Dominant and recessive is based on the environment. Due to that the gene altered itself or by mutation it express. It simple they are characters from the gene of a same organism. [ tall character in plant and short is in another plant but gene is same (allele) ]

Environment is the main facter for any mutaton naturally...

It may help U

Bye

Shiva

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It's just addition to previous reply:
it's that over 90% mutations in coding regions are recessive but some mutations are known to be dominant. Recessive mutation is the one that leads to loss of function but you can introduce another allele on plasmid or paralog on the chromosome to substitute phenotype. On the other hand dominant mutation has strong phenotype that is less likely be masked by supplying wildtype allele on plasmid or paralog elsewhere on the chromosome.
Again it's the outcome of mutation and not the gene which is dominant or recessive.

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