1.    a) The F₁ are all Bb.        b) Bb x Bb  - 1 BB: 2 Bb: 1 bb, 3 black : 1 yellow

2.    a) black fur (BB or Bb)  x  yellow fur (bb)
       b) BB x bb -  all Bb, all black  or Bb x bb -  1 Bb:1bb, 1 black: 1 yellow
       c) black fur - Bb, yellow fur - bb, offspring - bb

3.    a) BB or Bb x BB or Bb
       b) BB x BB - all BB, all black  or
           BB x Bb (or Bb x BB) - 1 BB: 1 Bb, all black or
           Bb x Bb  - 1 BB: 2 Bb: 1 bb, 3 black : 1 yellow
       c) both parents - Bb, offspring bb

4.                P₁ = BBTT x bbtt                F₁ = 4 BbTt : 0, all black with long tails
    a) BbTt and BbTt
    b) BbTt x BbTt
          genotype ratio:
            F₂ = 1 BBTT : 2 BBTt : 2 BbTT : 4 BbTt : 1 BBtt : 2 Bbtt : 1 bbTT : 2 bbTt : 1 bbtt
          phenotype ratio = 9/16 black with long tails (B_T_)
                                     3/16 black with short tails (B_tt )
                                     3/16 yellow with long tails (bbT_ )
                                     1/16 yellow with short tails (1 bbtt)

5.    a)  black, short-tailed  rugrat: BBtt or Bbtt                         yellow, short-tailed rugrat: bbtt
       b)              BBtt x bbtt:                                                Bbtt x bbtt:
                        4 Bbtt : 0                                                1 Bbtt : 1 bbtt
                all black with short tails                1/2 black, short tail; 1/2 yellow, short tail
       c) bbtt
       d)  black, short-tailed  rugrat: Bbtt                                      yellow, short-tailed rugrat: bbtt

6.    a) black, short-tailed rugrat:  BBtt or Bbtt         yellow, long-tailed rugrat: bbTT or bbTt
       b)        BBtt x bbTT:                                                BBtt x bbTt:
                    4 BbTt : 0                                        1 BbTt : 1 Bbtt, all black
            all black with long tails                1/2 with long tails: 1/2 with short tails

                   Bbtt x bbTT:                                                    Bbtt x bbTt:
            1 BbTt : 1 bbTt, all with long tails                1 BbTt : 1 bbTt : 1 Bbtt : 1 bbtt
         1/2 black : 1/2 yellow                                1/4 black, long tail; 1/4 yellow, long tail
                                                                        1/4 black, short tail; 1/4 yellow, short tail
       c) BbTt

The views and opinions expressed in this page are strictly those of the page author.
The contents of this page have not been reviewed or approved by the University of Minnesota.