well ... here is some info -- don't know that I can expand on it, but maybe it will help you.
I went to <a target=_blank class=ftalternatingbarlinklarge href="http://cancerweb.ncl.ac.uk/omd/
">http://cancerweb.ncl.ac.uk/omd/
</a>
and typed in <b>allele</b> and got <a target=_blank class=ftalternatingbarlinklarge href="http://cancerweb.ncl.ac.uk/cgi-bin/omd?action=Search+OMD&query=allele
">http://cancerweb.ncl.ac.uk/cgi...arch+OMD&query=allele
</a>
<genetics> Any one of a series of two or more different genes that occupy the same position (locus) on a chromosome.
Since autosomal chromosomes are paired, each autosomal locus is represented twice. If both chromosomes have the same allele, occupying the same locus, the condition is referred to as homozygous for this allele.
If the alleles at the two loci are different, the individual or cell is referred to as heterozygous for both alleles.
Then I typed in <b>variant</b> and got <a target=_blank class=ftalternatingbarlinklarge href="http://cancerweb.ncl.ac.uk/cgi-bin/omd?action=Search+OMD&query=variant
">http://cancerweb.ncl.ac.uk/cgi...rch+OMD&query=variant
</a>
Something which differs in form from another thing, though really the same; as, a variant from a type in natural history; a variant of a story or a word.