A HYPERVARIABLE MICROSATELLITE REVEALED BY INVITRO AMPLIFICATION OF A DINUCLEOTIDE REPEAT WITHIN THE CARDIAC-MUSCLE ACTIN GENE

  • 1 March 1989
    • journal article
    • research article
    • Vol. 44  (3) , 397-401
Abstract
The human genome contains approximately 50,000 copies of an interspersed repeat with the sequence (dT-dG)n, where n = .apprx.10-60. In humans, (TG)n repeats have been found in several sequenced regions. Since minisatellite regions with larger repeat elements often display extensive length polymorphisms, we suspected that (TG)n repeats ("microsatellites") might also be polymorphic. Using the polymerase chain reaction to amplify a (TG)n microsatellite in the human cardiac actin gene, we detected 12 different allelic fragments in 37 unrelated individuals, 32 of whom were heterozygous. Codominant Mendelian inheritance of fragments was observed in three families with a total of 24 children. Because of the widespread distribution of (TG)n microsatellites, polymorphisms of this type may be generally abundant and present in regions where minisatellites are rare, making such microsatellite loci very useful for linkage studies in humans.