Wiener, Alexander S.

AMERICAN
PHYSICIAN

In 1940 Alexander Wiener and Karl Landsteiner discovered the Rhesus, or Rh, factor in blood group typing, during the course of a series of scientific experiments. The two scientists injected guinea pigs and rabbits with the red blood cells of rhesus monkeys, and discovered that the experimental animals produced an antibody that agglutinated (caused the red blood cells to clump together) the rhesus red cells. In addition, they discovered that the antibody in the rabbits and guinea pigs' serum also agglutinated blood samples equivalent to approximately 85% of the human population. The percentage rate was later found to correspond to approximately 85% of the Caucasian population and an even larger percentage of the Black and Asian populations.

The agglutination meant that blood cells of the members of the 85% population group contained the same factor as did the rhesus monkeys. Their blood was termed Rh positive (Rh+), and the blood of the remaining 15% was termed Rh negative (Rh-). The Rh antibody reaction was, by its nature, acquired and not present at birth; that is, red blood cells of Rh+ individuals needed to be exposed to those of Rh- individuals in order for there to be an antibody reaction. The presence or absence of the Rh factor is of particular forensic importance in cases of disputed paternity, blood type and grouping inheritance, and genetic control. In everyday life, the presence or lack of the Rh factor has no bearing on health. It is only when the two blood types are mingled in an Rh-negative individual that problems ensue, since the Rh factor acts as an antigen in Rh persons, causing the production of antibodies.

Wiener hypothesized that Rh gene inheritance occurred in the form of a single gene on a single DNA locus. Since blood type and presence or absence of the Rh factor are genetic traits that are easy to test, and the blood type of an individual is related to parental blood types, blood group typing may be used legally to establish paternity.

It has become understood, since Wiener and Landsteiner's discovery of the Rhesus factor in 1940, that the Rh system is far more complex than the presence or absence of a single factor. There are now known to be three genes that combine to create Rhesus antigens (C, D, and E), all of which are encoded on a single chromosome (chromosome 1). There are two possible alleles at each locus: C or c, D or d, and E or e. One haplotype which contains c/C, d/D, and e/E is inherited from each parent. The resulting Rhesus type of the individual depends on which genotype they inherit. If a person inherits at least one of the C, D, or E antigens, they are Rh+. If they inherit two sets of cde genes, they will be Rh-.

Wiener made a lasting contribution to forensic science in his discovery and advancement of the concept of the Rhesus factor. By using blood typing and blood grouping technologies, it has become increasingly possible to identify unique individuals, whether suspects or victims, from among the entire population of humans.

see also Antibody; Antigen; Chromosome; DNA; Paternity evidence.