Answer:
A silver fur fox breeder found a platinum fur fox on his farm. When crossing this platinum fox with its silver foxes the offspring was always 1/2 platinum + 1/2 silver. When crossing platinum foxes with each other, get platinum and silver foxes in proportions 2/3 and 1/3 respectively. Indicates how many alleles of the gene that controls hair color are in the fox breeder's farm, their relationships and the genotypes of individuals.
As from the cross between platinum foxes both platinum and silver foxes are found we can deduce that the silver character is recessive (it is present in platinum foxes, but it does not manifest itself). The fact that the crossing between silver foxes produces a balanced offspring of platinum and silver foxes specifically tells us that platinum foxes are always heterozygous. This hybrid character of the platinum foxes would also explain why by crossing them with each other the ratio of 2: 3 instead of 3: 1 is obtained, the characteristic proportion obtained from the cross between heterozygous individuals for a character, since they are not counted homozygous individuals in the offspring (probably the gene responsible for platinum character is lethal in homozygosis). In this way the crosses indicated in the statement could be:
(pt + → platinum fur; pt → silver fur) pt + pt Platinum x ptpt Silver gametes pt + pt pt
pt + pt gametes
pt
pt + pt Platinum 1/2
ptpt Silver 1/2
pt + pt Platinum
x pt + pt Platinum gametes pt + pt pt + pt
pt + pt gametes
pt +
pt + pt + Platinum
pt + pt Platinum 1/3
pt
pt + pt Platinum 1/3
ptpt Silver 1/3