When crossing aquarium fish with a simple and golden color, offspring appeared, all of which had a simple color.

When crossing aquarium fish with a simple and golden color, offspring appeared, all of which had a simple color. What traits will the descendants of the 2nd generation have, obtained from the crossing of the 1st generation?

In this problem, inheritance occurs according to the type of complete dominance. Since 100% of the offspring have one color, we conclude that two homozygous organisms were crossed. The simple color gene is dominant (A), the gold gene is recessive (a).

P: AA (simple) x aa (gold);

G: A x a;

F1: Aa – 100% all offspring of the first generation have a simple color.

F1: Aa x Aa (individuals of the first generation are crossed);

G: A, a x A, a;

F2: AA – 25% simple paint;

Aa – 50% simple painting;

aa – 25% gold color.