Question

reindeer genetics
punnett squares, genotypes, & phenotypes
since gregor mendel was so successful in his work with pea plants, santa needed his help to select for the best traits in his reindeer herd. use your knowledge of genetics to answer the following questions.
part 1: use data from the table to write phenotypes for these genotypes

trait	dominant	recessive
nose color	black (n)	red (n)
ability to fly	non - flyer(f)	can fly (f)

1. aa -
2. nn -
3. aa -
4. ff -
5. ff -

part 2: label the ornaments as homozygous (ho) or heterozygous (he)
ornaments: ff, nn, aa, nn, ff, aa
6.
7.
8.
9.
10.
11.
part 3: use the table above to write genotype(s) for these phenotypes

1. heterozygous tall antlers
2. red nose
3. black nose
4. cannot fly
5. homozygous tall antlers
6. can fly
7. heterozygous non - flyer
8. homozygous dominant nose

part 4: use punnett squares to answer the following questions. show your work.

1. fill in the punnett square if two red - nosed reindeer were to mate. what is the probability that their offspring will also have a red nose?

red nose
black nose

Explanation:

Step1: Determine Genotype of Red - nosed Reindeer

Red nose is a recessive trait (from the table: Nose Color - Dominant: Black (N), Recessive: Red (n)). So a red - nosed reindeer must have the genotype \(nn\) (homozygous recessive) because the recessive trait is only expressed when there are two recessive alleles. So both parents, being red - nosed, have the genotype \(nn\).

Step2: Set up the Punnett Square

When we set up the Punnett Square for a cross between two \(nn\) individuals, we put one parent's alleles along the top and the other parent's alleles along the side. Since both parents have \(n\) alleles, the top row will have \(n\) and \(n\), and the side column will have \(n\) and \(n\).

	\(n\)	\(n\)
\(n\)	\(nn\)	\(nn\)

Step3: Calculate Probabilities

Looking at the Punnett Square, all four possible offspring genotypes are \(nn\). Since \(nn\) is the genotype for red nose, the number of red - nosed offspring (genotype \(nn\)) is 4 out of 4, and the number of black - nosed offspring (which would require at least one \(N\) allele, but there are no \(N\) alleles in the parents) is 0 out of 4. So the probability of red nose is \(\frac{4}{4}=1\) (or 100%) and the probability of black nose is \(\frac{0}{4} = 0\) (or 0%).

Answer:

For the Punnett Square:

	\(n\)	\(n\)
\(n\)	\(nn\)	\(nn\)

Red nose: \(100\%\) (or \(\frac{4}{4}\))
Black nose: \(0\%\) (or \(\frac{0}{4}\))