An F1 animal has 1 copy of every gene from each of its inbred parents.
During meiosis in this animal, recombination events randomly cause
exchange of chromosomal segments so that every F1 haploid gamete is
gentically unique and contains a mixture of the parental gene copies.
An F2 animal is formed from the fusion of 2 such F1 gametes. Chromosomal
regions which lie close together are less likely to be seperated during
recombination and therefore tend to co-segragate. Co-segragation of a
marker with a trait-causing gene/locus is the basis of linkage.
