duplication (in genetics) The doubling or repetition of part of a chromosome, which generally originates during the crossing over phase of meiosis. Occasionally this type of chromosome mutation may have beneficial effects on a population. For example, a beneficial duplication resulted in the evolution of four types of haemoglobin in humans and apes from a single form. One of these types of haemoglobin (gamma or fetal haemoglobin) has a greater affinity for oxygen and maximizes fetal uptake of oxygen from the mother's blood.

duplication The presence or creation of two copies of a DNA segment; usually the term is preceded by the unit of duplication (e.g. exon duplication, gene duplication, partial gene duplication).

duplication A chromosomal aberration in which more than one copy of a particular chromosomal segment is produced within a chromosome set.

duplication A chromosomal aberration in which more than one copy of a particular chromosomal segment is produced within a chromosome set.