Maternal–foetal ABO incompatibility is a common haematological problem affecting the newborn. In general, haemolysis is minimal and the clinical course is relatively benign, rarely causing escalating levels of hyperbilirubinaemia and significant anaemia commonly associated with the Rh haemolytic disease of the newborn (HDN). The hypothesis that ABO blood systems behave like the HLA system in relation to mother-conception tolerance-rejection mechanisms was tested in 983 mother–infant pairs. According to this hypothesis, heterozygotes carrying a paternal gene that is not present in their mother should be better tolerated than homozygotes. Significantly more BO infants born to AO mothers, AO infants born to BO mothers, and less significantly AO infants born to OO mothers confirm the hypothesis. These data strongly support the hypothesis that at least two foeto–maternal systems influence the destiny of pregnancies: the classical known incompatibility system, which operates late in pregnancy, and a new one, which is based on the induction of maternal tolerance early in pregnancy: maternal tolerance seems to be better elicited by heterozygous eggs or embryos carrying a gene not present in the mother. The data also support the hypothesis that sex ratio is influenced by foeto–maternal tolerance-rejection mechanisms associated with the ABO system.

Enzyme typing of fresh lysates and their stains was performed on a heterogeneous Indian population sample. The polymorphic forms namely *A/*A, *A/*B, *B/*B and *C/*B and their gene frequencies were determined. Studies on paired samples of menstrual bloodstains along with donors’ blood showed identical patterns in the zymogram. Laboratory prepared bloodstains on contamination with semen yielded inconsistent results.

Isoenzyme band patterns of esterase D have been studied in blood, vaginal swabs free from semen, seminal fluid and their stains. ESD polymorphism was demonstrated in all body fluids tested. One hundred and sixty two blood samples were analysed using starch agarose gel electrophoresis technique and the gene frequencies were estimated as ESD*1 = 0.765 and ESD*2 = 0.235. Stability studies carried out under different climatic conditions have revealed that the genetic marker is more stable in blood stains than in stains of semen and vaginal secretion.

This study reports the successful detection of ABO blood group specific substances from freshly cut finger and toe nails obtained from 123 ‘donoes’. Both mixed haemagglutination and absorption-elution techniques were employed.

Inhibtion reactions of 10 nonspecific lectins have been examined using a panel of 22 simple and derivative sugars. The results of haemagglutination inhibition reactions suggest that ten ten extracts, which apparently behave as nonspecific lectins, in fact, are highly specific with respect to the binding of saccharides. They possess multiple binding sites and could be converted into blood group specific lectins in the presence of certain inhibiting sugar (s). Six seed extracts namely Terminalia bellirica. Terminalui citnmi. Eucatypus statgnana, Ficus tnfectona. Monu alba and Vitna catiant after partial inhibition with certain carbohydrates, behaved like anti-(A+B). Three lectins (cassia siamea. Trichosanthus anguina. Ficus infectoria)could be convened into anti-(A+H) specific and one (Acalypha indira) into anti-(B+H). One lectin each could be converted into anti-A (Ficus infectoria) and anti-H (Trichosanthus anguina). While two lectins (Eugenia jamholana. Terminalia bellirica) could be converted into anti-B specific reagents after treatment with appropriate inhibiting sugars.

Genetic manifestations (blood groups, polymorphic enzymes) in biological evidences have extensively been utilized in forensic investigations. The last decade or so has witnessed a large amount of research work especially on the stability studies from blood stains. But the literature is sparse so far as the studies of enzyme typing in human dental pulp is concerned (Petersen and Heide, 1974; Turowska and Trela, 1977; Whittaker and Rothwell 1981; Henke et al., 1982 and Imai et al., 1984). The studies especially when the dental evidence could be used assume considerable significance in case of mass disasters, bride burning and general cases of arson where bodies are received either burnt, charred or badly mutilated and need to be identified. Whittaker and Rothwell (1981) observed that in some air disasters dental evidence alone has been responsible for the identification upto 40 percent of victims. Further, when a dead body is in advance stage of decomposition and only skeleton is left, teeth (with pulp) can still serve as a standard in place of blood (Petersen and Heide, 1974 and Lele et al., 1977).

Various procedures such as sodium dodecyl sulphate gel electrophoresis requiring monospecific human Hp antiserum, an acid extraction technique and a chloroform extraction method have been in use to avoid the trailing of haemoglobin deterioration products, while determining the haptoglobin types from dried bloodstains. The first two methods, i.e., SDS gel electrophoresis and acid extraction technique, involve lengthy procedures and are uneconomical for routine analysis. The chloroform extraction technique, though simpler and less time consuming, has a drawback; the extractor, i.e. 10% sucrose solution, recommended in this method, is a poor solvent. A modification of the chloroform extraction method using Tris-HCI buffer was employed in the present study, wherein more than 600 dried bloodstains kept under various states of preservation, were tested by non-gradient vertical Polyacrylamide gel electrophoresis. It was possible to determine correctly the haptoglobin phenotypes of dried bloostains nearly two years old by this method.

As yet, there is no report available on the stability studies of 6-phosphogluconate dehydrogenase enzyme in India. 469 bloodstains prepared in the laboratory using a variety of substrates commonly encountered in case examination have been analysed by starch gel electrophoresis. The utility of this parameter under various climatic conditions prevalent in India has also been evaluated. Except in the cases of relatively fresh samples of blood, the PGD isoenzyme system seems not to be very suitable in Indian conditions.

One hundred and ten pairs of blood and semen samples and their stains were studied to type glyoxalase 1 (GLO 1) isoenzymes using agarose-starch medium. A good agreement was observed between the phenotypes expressed in blood and semen samples of the same donor. No GLO 1 activity however could be demonstrated in the vaginal swabs tested. The gene frequencies of GLO 1 polymorphs in Himachal population has been worked out and their stability studies carried out at -12 degrees C and at room temperature.

One hundred and twenty bloodstains of a heterogeneous population have been successfully typed for the esterase D enzyme. Stability studies of the enzyme in bloodstains stored at room temperature and in lysates stored at —20°C and 4°C have been carried out. Frequencies of EsD phenotypes in Indian populations have also been worked out.