The C3 complement system was examined in our Danish material of normal families, which had earlier been examined for 59 marker systems, and in a myotonic dystrophy family material. A total of 8 alleles were recognized, with allele frequencies as follows: C3*S = 0.7902, C3*F = 0.2018, C3*S rare (3 lumped together) = 0.0036, C3* F rare (2 lumped together) = 0.0024; a silent allele was recognized in three families and its frequency to C3*QO = 0.002. The distribution of unrelated inviduals did not deviate significantly from the Hardy‐ Weinberg expectation, it was not siginicantly different between the sexes, and the for none of the mating types was there any significant deviation from the expected ratios of children. As to linkage relationships of C3 with market systems and with myotonic dystrophy, there was evidence (most of it first presented at the 6th International Congress of Human Genetics, Jerusalem 1981) for synteny with ABH secretion (Se): C3‐Se (males) ẑ= 4.35, θC = 0.12 and with Lewis secretion (LES): C3‐LES (males ẑ= 3.63, θC = 0.04). There were indicative or suggestive lod scores for Se‐PEPD (males & females ẑ= 2.41, θC = 0.00), C3‐Lu (ẑ= 1.88, θC = 0.15), C3‐DM (ẑ= 1.69, θC = 0.06) and PEPD‐C3 (male ẑ= 0.95, θC = 0.17). The most likely sequence of these 6 systems would appear to be LES‐C3‐DM‐(Se‐PEPD)‐Lu and the synteny would reside on chromosome 19.

14 cases of severe thrombocytopenia in one family are presented. Case histories, clinical examination, analyses of platelets, haemoglobin, reticulocytes, leucocytes, eosinophilocytes, differential counts of leucocytes, serum immunoglobulin IgA, IgM, IgG, IgE concentrations, complement fixing platelet antibodies, isohaemagglutinins, colour perception, determination of red cell and serum groups as well as HL-A types were obtained from a total of 59 members of the family. The in vitro blast transformation response of blood lymphocytes was studied in 6 patients and 45 relatives. The pattern of transmission of the disease was in full agreement with X-linked recessive inheritance. Investigation of the immune system revealed impaired responses to microbial antigens in the 6 patients so studied. All relatives examined had normal haematological status, whereas approximately half showed a subnormal response to one microbial extract. The low responders were evenly distributed within the family, and it was not possible to correlate low response and presumed carrier state.

We present a complete ancient human genome and oral microbiome sequenced from a piece of resinous "chewing gum" recovered from a Stone Age site on the island of Lolland, Denmark, and directly dated to 5,8585,661 cal. BP (GrM13305; 5,007±11). We sequenced the genome to an average depthofcoverage of 2.3× and find that the individual who chewed the resin was female and genetically more closely related to western huntergatherers from mainland Europe, than huntergatherers from central Scandinavia. We use imputed genotypes to predict physical characteristics and find that she had dark skin and hair, and blue eyes. Lastly, we also recovered microbial DNA that is characteristic of an oral microbiome and faunal reads that likely associate with diet. The results highlight the potential for this type of sample material as a new source of ancient human and microbial DNA.