For summer squash, the dominant allele Y for gene 1 leads to yellow color while the recessive allele y leads to green color. Alleles of gene 2 can prevent color formation, with the dominant allele W leading to white squash while the recessive allele w does not interfere with color development. How many phenotypes would be observed among the offspring of the following cross: YyWw x YyWw

Three phenotypes:

Explanation:

Available data:

                        Recessive allele y ⇒ green

                         Recessive allele w ⇒ Does not prevent color

Cross:

Parentals) YyWw        x     YyWw

Gametes) YW, Yw, yW, yw

                 YW, Yw, yW, yw

Punnett square)     YW          Yw           yW           yw

                YW      YYWW    YYWw     YyWW      YyWw

                 Yw      YYWw     YYww      YyWw      Yyww

                 yW      YyWW     YyWw      yyWW      yyWw

                 yw       YyWw      Yyww      yyWw      yyww

F1) Genotype

    Phenotype

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