Which of the following is a characteristic of uniparental disomy (UPD)?

Uniparental disomy (UPD) is a genetic condition in which an individual inherits two copies of a chromosome from one parent and no copies from the other parent. This means that the individual receives both homologous chromosomes from either the mother or the father, rather than one from each parent. This unique inheritance pattern can lead to various genetic implications, particularly in cases where imprinted genes are involved or when a recessive disorder is present in the inherited chromosomes.

The correct choice reflects this characteristic of UPD, emphasizing that both copies of the chromosomes are derived from the same parental source, while the other parent provides no contribution to that particular chromosome pair. Understanding UPD is crucial as it can significantly influence genetic expression and the phenotypic outcome in the individual.