Flower color in a plant is determined by two genes R and Y. the dominant R allel
ID: 143608 • Letter: F
Question
Flower color in a plant is determined by two genes R and Y. the dominant R allele produces a red pigment from a colorless (white) precursor. The recessive r allele is a null. The dominant Y allele produces a yellow pigment from a different colorless (precursor). The recessive y allele is a null. The simultaneous presence of a dominant R and dominant Y allele produces orange coloration of the flowers. What ratio F2 flower color phenotypes would be produced if a pure breeding red flowered parent was crossed with a pure breeding yellow flowered parent? P: R/R; y/y x r/r; Y/Y F2: Genotypes and phenotypes with corresponding ratios: please show how u get the ratios etc
Explanation / Answer
This is a polygenic inheritance phenomenon
Alleles of pure breeding red flowering parent is Ry/Ry
Alleles of pure breeding red flowering parent is rY/rY
Genotype of F1 progeny would be heterozygote RrYy or R/r; Yy and the alleles they would produce would be RY, Ry, rY and ry
Lets draw the punnett square for F2 generation
say (r) is red, (y) is yellow, (o) is orange and (c) is colorless and consider that the presence of either R or Y or both R and Y alleles in genotype would result in producing Orange flowers.
Therefore the phenotypic ratio between Orange:Red:Yellow:Colorless flowers are 9:3:3:1
The genotypic ratio between RRYY:RRYy:RRyy:RrYY:RrYy:Rryy:rrYY:rrYy:rryy is 1:2:1:2:4:2:1:2:1
RY Ry rY ry RY RRYY (o) RRYy (o) RrYY (o) RrYy (o) Ry RRYy (o) RRyy (r) RrYy (o) Rryy (r) rY RrYY (o) RrYy (o) rrYY (y) rrYy (y) ry RrYy (o) Rryy (r) rrYy (y) rryy (c)Related Questions
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