A homozygous dragon with a red skin of normal growth was crossed with a yellow dwarf dragon. Have crossed their descendants; how likely can you expect red dragons with normal growth?
Let’s designate the gene that causes the dragon skin to be red as K, then the gene for the yellow skin will be k.
Let’s designate the gene for normal dragon growth as L, then the gene for dwarfism will be l.
A homozygous red-skinned dragon with normal growth will have the KKLL genotype and produce the same type of KL germ cells.
A dwarf dragon with a yellow skin will have the kkll genotype and produce germ cells of the same type – kl.
All F1 offspring will be heterozygous KkLl pups with red skins and normal growth for both traits. These hybrids will be able to produce four types of germ cells – kl, KL, kL, Kl.
When they reach sexual maturity, they will interbreed, which will lead to the formation of offspring, including the following options:
cubs with red skin and normal growth (4 KkLl, KKLL, 2KkLL, 2KKLl) – 56.25%;
cubs with red skin and dwarf growth (2Kkll, KK ll) – 18.75%;
cubs with yellow skin and dwarf growth (kkll) – 6.25%;
cubs with yellow skin and normal height (kkLL, 2kkLl) – 18.75%.
Answer: The probability of a red dragon with normal growth in the offspring of diheterozygous hybrids is 56.25%.