The Following Coat Colors Are Determined by Alleles at One $\text { Cross }$

Essay

The following coat colors are determined by alleles at one locus in horses:
palomino = golden coat with lighter mane and tail
cremello = almost white
chestnut = brown
The following table gives ratios obtained in matings of the above varieties:
$\text { Cross }$ $\quad$$\quad$$\text { Parents }$ $\quad$$\quad$$\quad$$\text { Offspring }$
$\begin{array}{ll}\hline \\1 \text { cremello } \mathrm{X} \text { cremello } & \text { all cremello } \\2 \text { chestnut } \mathrm{X} \text { chestnut } & \text { all chestnut } \\3 \text { cremello } \mathrm{X} \text { chestnut } & \text { all palomino } \\4 \text { palomino } \mathrm{x} \text { palomino } & 1 / 4=\text { chestnut }\\&1 / 2=\text { palomino }\\&1 / 4=\text { cremello }\end{array}$
Assign gene symbols for the genetic control of coat color on the basis of these data.
Diagram the last two matings.