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In mice, the dominance pattern reveals that black fur dominates over white, while long fur dominates over short. 


What is the probability that a white mouse that is homozygous for long fur and a mouse heterozygous for both traits can have offspring with short white fur?


A. 0

B. 0.25

C. 0.5

D. 0.75

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Last updated date: 20th Jun 2024
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Answer
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Hint:

  • Determine the genotypes of the parents.

  • Use a Punnett square to determine the possible genotypes of the offspring.

  • Determine the probability of offspring with short white fur.


Complete step-by-step Answer: In the world of genetics, traits are often inherited from parents to offspring in a predictable manner. This predictability is due to the presence of genes, which are segments of DNA that carry instructions for developing various characteristics. Genes can have different versions, called alleles, and the combination of alleles an individual inherits determines their traits.


In the case of fur color and fur length in mice, black fur is dominant to white fur, and long fur is dominant to short fur. This means that a mouse with at least one dominant allele for fur color (B) will have black fur, and a mouse with at least one dominant allele for fur length (L) will have long fur.


Now, let's consider the parent mice:


White mouse that is homozygous for long fur: wwLL


This mouse has two recessive alleles for fur color (ww) and two dominant alleles for fur length (LL). This means that it will have white fur and long fur.


Mouse heterozygous for both traits: BbLl

This mouse has one dominant allele and one recessive allele for fur color (Bb) and one dominant allele and one recessive allele for fur length (Ll). This means that it will have black fur and long fur.


Using a Punnett square, we can determine the possible genotypes of the offspring. A Punnett square is a table that shows all possible combinations of alleles that can be passed on from parents to offspring. In this case, the Punnett square looks like this:



Bb

Bb

Ll

BLLL

BllL

Ll

BLLL

BllL

ll

Bbll

bbll

ll

Bbll

bbll


From the Punnett square, we can see that there are four possible genotypes for the offspring:


BLLL: Black fur, long fur

BllL: Black fur, short fur

Bbll: Black fur, short fur

bbll: White fur, short fur


As we are interested in the probability of offspring with short white fur, we only need to consider the genotype bbll. From the Punnett square, we can see that there is one possible combination of alleles that will produce offspring with this genotype: bbll. This means that the probability of offspring with short white fur is 1 out of 16, or 1/16.


Hence the correct answer is Option B


Note: It is important to remember that the probability of offspring with short white fur is only 1/16. This means that it is relatively unlikely for this genotype to occur. However, it is still possible, and it is important to understand the principles of genetics in order to predict the possible outcomes of crosses between different organisms.