In horses, B = black coat, b = brown coat, T = trotter, and t = pacer. What genotype is a black trotter that has a brown pacer offspring?

to get brown from black Bb

to get pacer from trotter Tt
because
brown pacer needs two recessive bs and two recessive ts, one each from father and mother.

BbTt

To determine the genotype, we need to consider the alleles inherited from each parent and how they are passed on to the offspring.

Given:
B = black coat
b = brown coat
T = trotter
t = pacer

From the question, we can deduce the following information:

1. The black trotter (parent) must have the genotype BBTT (homozygous for black coat and trotter).

2. The offspring is brown (so it must have at least one brown allele) and is a pacer (so it must have at least one pacer allele).

3. Since the parent horse is black, it must carry at least one black allele.

Now, let's work out the possible genotypes for the offspring:

If the black trotter carries the brown allele, it must be heterozygous for coat color (Bb). Therefore, it can pass on either the B or b allele to the offspring. Similarly, it can pass on either the T or t allele for the gait.

Possible genotypes for the offspring:
1. BbTt (black carrier trotter)
2. Bbtt (black carrier pacer)

Since the offspring is a brown pacer, the genotype must be Bbtt.

To summarize, the genotype of the black trotter that has a brown pacer offspring is BbTT, and the genotype of the offspring is Bbtt.

To determine the genotype of a black trotter that has a brown pacer offspring, we need to understand the principles of genetic inheritance.

In this case, the traits are coat color and gait type. Coat color is determined by the presence of either the dominant allele B (for black coat) or the recessive allele b (for brown coat). Gait type is determined by the presence of either the dominant allele T (for trotter) or the recessive allele t (for pacer).

Let's say the genotype of the black trotter parent is BbTt. This means that the horse carries one copy of the dominant black coat allele (B) and one copy of the recessive brown coat allele (b), as well as one copy of the dominant trotter allele (T) and one copy of the recessive pacer allele (t).

To determine the genotype of its brown pacer offspring, we need to consider the possible combinations of alleles that can be passed down from the parent.

When the black trotter parent reproduces, it randomly passes on one of its alleles for each trait to its offspring. In this case, there are four possible combinations:

1. Offspring genotype: BT (black trotter)
This means the offspring inherits the dominant black coat allele (B) from the parent and the dominant trotter allele (T) and becomes a black trotter. However, this is not the genotype we're looking for.

2. Offspring genotype: Bt (black pacer)
This means the offspring inherits the dominant black coat allele (B) from the parent and the recessive pacer allele (t), becoming a black pacer.

3. Offspring genotype: bT (brown trotter)
This means the offspring inherits the recessive brown coat allele (b) from the parent and the dominant trotter allele (T), becoming a brown trotter.

4. Offspring genotype: bt (brown pacer)
This means the offspring inherits the recessive brown coat allele (b) and the recessive pacer allele (t), becoming a brown pacer. This is the genotype we're interested in.

So, the genotype of a black trotter that has a brown pacer offspring would be Bbtt.