Question

1. tongue rolling - roller dominant, nonroller recessive - use ts

a. my trait is roller b. i have the dominant/recessive trait. c. my letters are t,t
d. cross: tt x tt
genotypic ratio:
phenotypic ratio:

1. hitch-hikers thumb - straight thumb dominant, hitch-hiker thumb recessive - use hs

a. my trait is hitch-hiker b. i have the dominant/recessive trait. c. my letters are h,h
d. cross: hh x hh
genotypic ratio:
phenotypic ratio:

1. bent little finger - bent dominant, straight recessive - use fs

a. my trait is straight b. i have the dominant/recessive trait. c. my letters are f,f
d. cross: ff x ff
genotypic ratio: 4/4 ff
phenotypic ratio: 4/4 straight

1. interlaced fingers - left thumb over right dominant, right over left recessive - use is

a. my trait is right b. i have the dominant/recessive trait. c. my letters are i,i
d. cross: ii x ii
genotypic ratio: 1/4 ii 2/4 ii 1/4 ii
phenotypic ratio:

1. big toe and second toe - second toe longer dominant, bit toe longer recessive - use ts

a. my trait is big toe longer b. i have the dominant/recessive trait. c. my letters are t,t
d. cross: tt x tt
genotypic ratio: 4/4 tt
phenotypic ratio: 4/4 big toe longer

Explanation:

Step1: Analyze Cross 6 (TT × tt)

Identify genotypes from Punnett square: TT, Tt, Tt, tt.
Genotypic ratio: $\frac{1}{4}$ TT, $\frac{2}{4}$ Tt, $\frac{1}{4}$ tt (simplified: 1:2:1)
Phenotypic ratio: Roller (TT, Tt) : Nonroller (tt) = $\frac{3}{4}$ : $\frac{1}{4}$ (3:1)

Step2: Analyze Cross 7 (HH × Hh)

Identify genotypes from Punnett square: HH, HH, Hh, Hh.
Genotypic ratio: $\frac{2}{4}$ HH, $\frac{2}{4}$ Hh (simplified: 1:1)
Phenotypic ratio: Straight thumb (HH, Hh) : Hitch-hiker thumb = $\frac{4}{4}$ : 0 (4:0, all straight)

Step3: Correct Cross 8 (Ff × Ff)

Fix Punnett square: F & f from each parent. Genotypes: FF, Ff, Ff, ff.
Genotypic ratio: $\frac{1}{4}$ FF, $\frac{2}{4}$ Ff, $\frac{1}{4}$ ff (1:2:1)
Phenotypic ratio: Bent finger (FF, Ff) : Straight finger (ff) = $\frac{3}{4}$ : $\frac{1}{4}$ (3:1)

Step4: Analyze Cross 9 (II × ii)

Identify genotypes from Punnett square: Ii, Ii, Ii, Ii.
Genotypic ratio: $\frac{4}{4}$ Ii (4:0)
Phenotypic ratio: Left over right (Ii) : Right over left = $\frac{4}{4}$ : 0 (all left over right)

Step5: Correct Cross 12 (Tt × tt)

Fix Punnett square: T/t from first parent, t/t from second. Genotypes: Tt, Tt, tt, tt.
Genotypic ratio: $\frac{2}{4}$ Tt, $\frac{2}{4}$ tt (1:1)
Phenotypic ratio: Second toe longer (Tt) : Big toe longer (tt) = $\frac{2}{4}$ : $\frac{2}{4}$ (1:1)

Answer:

Problem 6

Genotypic Ratio: 1 TT : 2 Tt : 1 tt
Phenotypic Ratio: 3 Roller : 1 Nonroller

Problem 7

Genotypic Ratio: 1 HH : 1 Hh
Phenotypic Ratio: 4 Straight thumb : 0 Hitch-hiker thumb

Problem 8

Genotypic Ratio: 1 FF : 2 Ff : 1 ff
Phenotypic Ratio: 3 Bent finger : 1 Straight finger

Problem 9

Genotypic Ratio: 4 Ii : 0 other genotypes
Phenotypic Ratio: 4 Left thumb over right : 0 Right over left

Problem 12

Genotypic Ratio: 1 Tt : 1 tt
Phenotypic Ratio: 1 Second toe longer : 1 Big toe longer