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Cross a heterozygous axial, hybrid round seed plant with a hybrid axial, heterozygous round seed plant. Only list the phenotypic ratio at the end.

Respuesta :

marianaegarciaperedo

Answer:

The phenotypic ratio is 9:3:3:1

  • 9/16 individuals with axial flowers and rounded fruits, R-A-
  • 3/16 individuals with terminal flowers and rounded seeds, R-aa
  • 3/16 individuals with axial flowers and wrinkled seeds, rrA-
  • 1/16 individuals with terminal flowers and wrinkled seeds, rraa

Explanation:

We need to cross a heterozygous axial, hybrid round seed plant with a hybrid axial, heterozygous round seed plant. When referring to a hybrid plant for a trait, we are meaning that the plant is heterozygous for that trait.

Let us assume that round is the dominant trait, codified by a diallelic gene, so

  • R is the dominant allele
  • r is the recessive allele

Let us also assume that axial is the dominant trait, so

  • A is the dominant allele
  • a is the recessive allele    

Cross:

Parentals)   RrAa  x  RrAa

Gametes)  RA, Ra, rA, ra

                 RA, Ra, rA, ra

Punnett Square)     RA           Ra          rA          ra

                   RA      RRAA    RRAa      RrAA     RrAa

                   Ra      RRAa     RRaa       RrAa     Rraa

                   rA       RrAA     RrAa       rrAA      rrAa

                   ra       RrAa      Rraa        rrAa       rraa

F1) Among the progeny, we expect to observe the following phenotypic ratio:

  • 9/16 individuals with axial flowers and rounded fruits, R-A-
  • 3/16 individuals with terminal flowers and rounded seeds, R-aa
  • 3/16 individuals with axial flowers and wrinkled seeds, rrA-
  • 1/16 individuals with terminal flowers and wrinkled seeds, rraa

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