In some cases it can be difficult to distinguish between co-dominance and incomp

Question

In some cases it can be difficult to distinguish between co-dominance and incomplete dominance using genetic crosses.

Our discussion in class referred to a diploid species where flower color was coded by a single locus where AA=red, aa=white and Aa=pink. The pink color could be caused by only a half of red pigment in heterozygotes (dose effect), or because the presence of red and white pigment gives pink (co-dominance).

Things would get much easier if, instead of a diploid plant, we were using a tetraploid plant. In that case, AAAA=red, aaaa=white, AAaa=pink. In 200 words or fewer, describe how you could use genetic crosses to distinguish between co-dominance vs. dose effect. In the case of co-dominance, assume that the amount of pigment produced by an allele is independent from the number of alleles present.

Explanation / Answer

Incomplete dominence is the phenomenon where dominent alleles do not completely express it self .this phenomenon is first studied in 4 o clock plant in which heterozygous flower are pink in colour.

Co dominence- when the heterozygous exiibits a mixture of both homozygotes .In a shorthorn cattle alleles for red and white coat is made up of red and white coat .effect of boath the alleles are equally conspicuous .there is no mixing of the effect of the two alleles.

Mltiple allele makes for many possible dominence relationship . an example ... A gene that specifies coat colour in rabbit is C gene . The C gene comes in four common allele C cch ch and c . A CC rabbit has black or brown fur

A cch cch rabbit has grayish fur

A ch ch rabbit has colour paint

and cc rabbit is with white fur

In this case the black C allele is completely dominent to all other the grayish colour is incopletely dominent to the colour paint and white fur . colour paint is completely dominent to the albino allele .

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