unequal crossing over
A genetics term referring to a type of chromosomal crossover where the exchange is not perfectly reciprocal, leading to duplication or deletion of genetic material.
Unequal crossing over can cause gene duplication or deletion.
乗換え alone means 'crossing over' in genetics, or 'transfer/change' in general. 不等乗換え specifies the unequal type.
相同組換え (homologous recombination) is a broader process that includes crossing over; 不等乗換え is a specific outcome of misaligned homologous recombination.
Compound of 不等 (unequal) + 乗換え (crossing over). The term is a direct calque from English 'unequal crossing over' used in genetics.