Question

1)In many species of flowering plants, the gene(s) responsible for flower color are incompletely dominant. A cross of a red rose and a blue rose will create what color(s) of flowers?

a red b blue c purple d both red and blue

2)Plant height in pea plants is controlled by a single gene. T is tall while t is short. Match the genotype on the left with possible progeny on the right. Note you are only given ONE genotype and not a cross. Choose all possible progeny for the genotype on the left.

TT ,Tt.tt

short only ,tall only or short or tall or both

Answer 1

1. Incomplete dominance is the inability of an allele of a gene to completely express over the other allele of the same gene. When two alleles which show incomplete dominance are crossed, the resulting progeny shows the parent phenotype as well as a new phenotype which is produced due to incomplete dominance.

So, Red (RR) × blue (rr) = Purple (Rr) in F1 generation.

If progenies of F1 are crossed, Rr × Rr = 1 RR (red), 2 Rr (purple), 1 rr (blue)

Option C

2. Tall (T) is dominant over short (t). So, T will express itself in heterozygous condition.

So, TT and Tt will be tall and tt will be short.

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