When we consider examples of incomplete dominance we take that of FOUR O CLOCK plant -
We say that alleles for red and white colour of flower are not completely dominant against each other. Hence in hybrid progeny we Say (as in standard textbooks) that pink colour appears due to "expression of single gene for pigmented flower which produces only pink colour (quantitative inheritance )"
In codominance concept we take example of SHORT HORNED CATTLE which again appears as same case white and red cattle produces roan coloured hybrid progeny but due to "juxtaposition of small patches of red and white colour hair"
The same principle can be applied to four o clock plant too. Suppose pink colour of flower is too due to juxtaposition of red and white coloured elements.
Then where is the difference between the two concepts?
Further the thing which puzzled me more was that - "initially cattle example was considered to be in complete dominance. Later it was CORRECTED to codominance " Also incomplete dominance is also known as "mosaic dominance" but actually mosaic happens in codominance. Kindly clarify my doubts