Disorders in chromosome number, or aneuploidies, are typically lethal to the embryo, although a few trisomic genotypes are viable. Sutton and Boveri's Chromosomal Theory of Inheritance states that chromosomes are the vehicles of genetic heredity.

Sturtevant devised a method to assess recombination frequency and infer linked genes' relative positions and distances on a chromosome on the basis of the average number of crossovers in the intervening region between… Whereas linkage causes alleles on the same chromosome to be inherited together, homologous recombination biases alleles toward an independent inheritance pattern

Chromosomal Theory of Inheritance — theory proposing that chromosomes are the genes' vehicles and that their behavior during meiosis is the physical basis of the inheritance patterns that Mendel observed. recombination frequency — average number of crossovers between two alleles; observed as the number of nonparental types in a progeny's population. homologous recombination — process by which homologous chromosomes undergo reciprocal physical exchanges at their arms, also crossing over. aneuploid — individual with an error in chromosome number; includes chromosome segment deletions and duplications.