Question

a geneticist notes that crossing a round radish with a long radish produces oval radish. when oval radishes were crossed with oval radishes the F2 generation had these phenotypes 100 long 200 oval 100 round radishes. Use symbols to explain the results obtained for the F1 and F2 generations. please help!!!!

Answer 1

If the shape of radish is under the control of one gene, for example A than we can say:

AA is dominant homozygous genotype-round radish phenotype,

aa is recessive homozygous genotype-long radish phenotype

If we cross round and long radish:

P: AA  x  aa

F1: Aa  Aa  Aa  Aa  

Aa is heterozygous genotype-oval phenotype

If we than cross the F1:

Aa  x  Aa

F2: AA  Aa  Aa  aa

This means that the ratio between the phenotypes woul be  1:2:1 (round:oval:long).