A deoxyribonucleic acid (DNA) molecule that carries a portion of all genetic material. Two homologous chromosomes carry the same collection of gene, but each gene can be represented by a different allele on the two homologues (a heterozygous individual). A gamete (egg or sperm) will receive one of these homologues, but not both. Humans have 22 pairs of autosomal homologous chromosomes and 1 pair of sex chromosomes.
Used to identify the position of a genetic variant within MR studies.

References
Other terms in 'Useful genetic terms ':
- Allele
- Copy number variation (CNV)
- Deoxyribonucleic acid (DNA)
- Gene
- Genetic variant
- Genotype
- Haplotype
- Heterozygous/heterozygote
- Homozygous/homozygote
- Linkage disequilibrium (LD)
- Locus
- Palindromic SNP
- Polygenic risk score (PRS)
- Polymorphism
- Rare variants
- Single nucleotide polymorphism (SNP)