I went to the Philadelphia Flower show with my friend. While we were there, we s
ID: 255475 • Letter: I
Question
I went to the Philadelphia Flower show with my friend. While we were there, we saw some amazing roses. (plants that have colorful flowers). We bought 2 true-breeding plants. One had YELLOW FLOWERS and SHARP THORNS. The other true-breeding plant had RED FLOWERS and DULL THORNS. We brought the plants home and crossed them to get hybrids. They ALL had YELLOW FLOWERS and SHARP THORNS. Answer the following based on crossing two of the hybrids with each other: 1) a) Assign letters to the alleles for each trait: b) Provide the genotypes for each of the following: i) Parent with YELLOW FLOWERS and SHARP THORNS i) Parent with RED FLOWERS and DULL THORNS ii) F1 Hybrid with YELLOW FLOWERS and SHARP THORNS Name the type of cross that is being performed when the two hybrids are crossed. Provide the PHENOTYPIC ratio for the F2 generation (remember to label your answer.) c) d)Explanation / Answer
a) Pure breeding plants with YELLOW FLOWERS and SHARP thorns can be depicted by YYSS
Pure breeding plants with RED FLOWERS and DULL THORNS can be depicted by yyss.
b)
c) When two hybrids are being crossed, it is termed as F2 generation cross. If two traits are involved as given in the question, then the cross is termed as Dihybrid Cross.
d) The phenotypic ratio for F2 generation can be calculated by means of punnet square as follows:
There are 4 distinct phenotypes:
The phenotypic ratio as evident from Punnet square is 9:3:3:1
YS Ys yS ys YS YYSS YYsS yYSS yYsS Ys YYSs YYss yYSs yYss yS YySS YysS yySS yysS ys YySs Yyss yySs yyss