A cross breed was made between white male dog and two different black female.the first female gave birth to eight black pups while the second gave birth to four white and three black pups,what are the likely genotypes of the male parent and the two female parent?

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asked Apr 20, 2015 in Other by Jenny (45 points)
    

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Because white is a recessive color, and black is the dominant color it is known that the male dog must have a genotype of "bb" because otherwise if it was "Bb" or "BB" it would appear a black (phenotype). Because the first female gave offspring that were all black, it must mean that the first female only has dominant genes "BB" so as to always cross with the male and make dominant offspring. The second female, who made a mix of offspring, must have a dominant and recessive trait in order to accomplish this. Filling out a genetic crossing table using these assumptions as below shows that our assumptions are correct and the male and female 1 will 100% of the time create dominant phenotypes (real world result: 100%). Meanwhile the male and female 2 will 50% of the time create a dominant phenotype (real world result: 43%) the closeness of these percentages is the proof that this is most likely their genotypes

  Male(bb)    
b b    
Bb Bb B Female1(bb)
Bb Bb B  
  Male(bb)    
b b    
Bb Bb B Female2(Bb)
bb bb b  

 

answered Oct 21, 2015 by reedinationer ~Rookie~ (102 points)

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