Lab Report - Mouse Genetics
(Two Traits)
In this virtual experiment, I bred “pure” mice with known genotypes that
exhibited specific fur and eye colors (black fur with black eyes, black fur with red
eyes, white fur with black eyes, white fur with red eyes). The purpose of this lab
was to learn how traits are passed on via dominant and recessive genes. Before
starting, my hypothesis was that some mice would have recessive genes passed on
to them. I bred two mice during each round, both with different genotypes. During
this experiment, I learned that two organisms, such as mice, can look similar or the
same while having different genotypes. For example, both mice will appear to have
black fur and black eyes. Yet, their genotypes are BbEe (the capital letters stand
for black fur; the lowercase letters stand for white fur). Hence, it is possible for
their litter traits to vary. In one round, I also learned that there can be equal (or
approximately equal) possibilities for each mouse in the litter to have specific
traits. At one point, I bred a mouse with white fur and red eyes (bbee) with a
mouse with black fur and black eyes (BbEe). The predicted fraction for each
genotype in the litter was 4/16 for each. Meaning that there is a 25% chance for
each genotype, if you were to convert the fractions to percentages. Another way
to test my hypothesis would be to have mice stored in cages for future breeding.
And each time they were bred, I could report the statistics of fur and eye color.
As I later learned, my hypothesis was not correct; I was wrong because there were
a variety of genes passed on, both dominant and recessive. As you can see, The
evidence from the Lab shows that if a mouse receives one trait of a particular
form, then the inheritance of the other trait will not be hampered because alleles
assort independently. However, it is observed that the traits for white fur and red
eyes are always inherited together. It can be a possibility that the genes of the
traits observed are present in a chromosome and are linked together or present at
a close proximity. If the genes are linked then the possibility of genes to get
separated decreases. In conclusion, there are wide possibilities when breeding mice
whom carry both dominant and recessive traits.