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In one type of dog, black spots (B) are dominant over brown spots (b) and long tails (L) are dominant over short tails (l). Complete a dihybrid cross for parents with the genotypes: BbLL × BBLl and answer the following in complete sentences.

1. Describe how you would set up a Punnett square for this cross.
2. List the likelihood of each possible offspring genotype.
3. List the likelihood of each possible offspring phenotype.

Respuesta :

You would draw a four by four punnett square. On top, your genotypes are the father's.  Across: BL bL BL bL Down: BL Bl BL Bl 

Genotypes                                                   Phenotypes
BBLl:25%                                                    Black Spot Long Tail: 100%
BBLL: 25%                                                 Black Spot Short Tail: 0%
BbLl: 25%                                                   Brown Spot Long Tail: 0%
BbLL: 25%                                                 Brown Spot Short Tail: 0%
BBll: 0% 
bbLL: 0%
bbLl: 0%
bbll: 0%
marianaegarciaperedo

Assuming genes that assort independently, do not interact, and express complete dominance, the expected genotypes are 25%  BBLL, 25% BBLl, 25%  BbLl, 25% BbLL. The expected phenotype is 100% black spots and long tails

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Available data:

Two diallelic genes. One codes for spots color. The other one codes for tail length.

Spots

  • B is the dominant allele and codes for back spots
  • b is the recessive allele and codes for brown spots

Tail length

  • L is the dominant allele and codes for long tail
  • l is the recessive allele and codes for short tail

Cross:

Parentals)         BbLL             x             BBLl

Gametes)   BL, BL, bL, bL             BL, BL, Bl, Bl

             

Punnett square)         BL         BL          bL           bL

                      BL      BBLL      BBLL      BbLL       BbLL

                      BL      BBLL      BBLL      BbLL       BbLL

                      Bl       BBLl       BBLl       BbLl        BbLl

                      Bl       BBLl       BBLl       BbLl        BbLl

1. Describe how you would set up a Punnett square for this cross.

To make the Punnett square, first, you need to define the parental genotypes. Then you need to define the gametes each parent contributes.

The gametes of one parent are placed in the upper part of the square, while those of the other parent are placed on the left side.

The square is filled with a combination of gametes.

2. List the likelihood of each possible offspring genotype.

F1)  Genotype

  • 4/16 = 25% BBLL, h0m0zyg0us dominant for both genes
  • 4/16 = 25% BBLl, h0m0zyg0us dominant for B gene, heter0zyg0us for L gene
  • 4/16 = 25% BbLL, h0m0zyg0us dominant for L gene, heter0zyg0us for B gene
  • 4/16 = 25% BbLl, heter0zyg0us for both genes.

 

3. List the likelihood of each possible offspring phenotype.

   

        Phenotype

  • 16/16 = 100% dogs with black spots and long tails, B-L-.

Note that the symbol - represents either a dominant or recessive allele.

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Related link: brainly.com/question/24675464?referrer=searchResults

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