milee99
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what is the difference between genetic polymorphism and allelic heterogeneity?
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| angel^Doctor
Forum Elite
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genetic polymorphism is when is when 1 gene has more than 1 normal type eg eye color, ABO blood grouping .. all are normal but at the same locus, there are many forms/ varietis/alleles in different population
locus heterogenicicy is when more than 1 genes ( different genes in different loci ) >> mutation in any of them give the sam clinical picture .. any mutation in different genes responsible for synthesis of collagen whether the enzyme or the collagen molecules itself all can produce osteogenic imperfecta.. another example is albenism ..
simple concept
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| paheli
It'sAllAboutGoodKarma
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also, in allelic heterogeneity, out of all genes present, only one is expressed.
in genetic polymorphism, all genes work in tandem for a desired effect/protein synthesis.
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| milee99
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thanks 
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| u3846158
Forum Newbie
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Posts: 7
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the question ask about allelic heterogeneity is not the same thing as locus hetrogeneity!
polymorphism usually means that the alteration of the sequence (not necessary in the gene) that are more tahn 1% of the populations.
there are many genetic polymorphism in human genome namely, single nucleotide polymorphism, microsateelite, minisatellite, number of copy variations (This are quite too difficult)
when a polymorphism occur in the gene, they may disrupt the aminoacid that the gene produce lead to negative or positive effect, we call this type of polymorphism like mutation.
the same disease or the same phenotype can cause from mutation of various of genes, that is the concept of locus heterogeneity, but in the same locus we can have different type of gene that we call allele (human have 2 alleles for 1 gene at a time)
the same phenotype may come from different allele compostions
example
ABO blood group
blood group A can have two genotypes : AA or AO this is the allelic heterogeneity.
these two concept cause confusion in genetic counseling that we cannot predict genotype directly from the phenotype.
http://clinicalgenetics.blogspot.com
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