Solved by a verified expert:Monohybrid genetic cross to determine dominant trait
This is the genetic problem that I need to understand how to
complete.

Sand lizards in white sands new mexico:
If for each species a lizard that was homozygous for the
dark Mc1r allele had been crossed with a lizard that was homozygous for the
light Mc1r allele the resulting F1 generation would have obtained the
percentage of light skinned offspring shown below in coloum 2. If they had gone
on to cross 2 offspring from the F1 generation, the resulting F2 generation
would have obtained the results shown in column 3 below.
for each of the 2 species state whether the light allele is
dominant or recessive to the dark Mc1r allele. Draw mating diagrams to support
your answer.It needs to show the crosses and the genotype and phenotype ratios
that result in the F1 anf F2 generations.

Lizard species % of light skinned lizards % of lizards in F2
in F1 generation generation
Sceloporus undulatus 100% 75%

Aspidoscelis inornata 0% 25%