Marianne Rasmuson

Genetic Heterogeneity and Gene Diversity in the Population of Punjab, Pakistan, Based on ABO and Rh(D) Blood Group Frequencies

AB0 and Rh(D) blood group data from more than 20,000 persons have been assembled from 14 cities in Punjab, Pakistan, and analysed for regional differentiation. The concept of the coefficient of gene differentiation was used to quantify the gene diversity, which has been compared to other such estimates from Europe and Japan.

Variation in genetic identity within kinships.

Genetic identity, which may be important for kin recognition, is the fraction of the genome that is identical by descent. It is, except for the parent-offspring relation, governed by probability and its variance depends on the number of segregating units during meiosis. Using the recombination index as an approximation of this number the variance for genetic identity has been estimated for different kinds of kinship.

Genealogy and gene trees

Heredity can be followed in persons or in genes. Persons can be identified only a few generations back, but simplified models indicate that universal ancestors to all now living persons have occurred in the past. Genetic variability can be characterized as variants of DNA sequences. Data are available only from living persons, but from the pattern of variation gene trees can be inferred by means of coalescence models. The merging of lines backwards in time leads to a MRCA (most recent common ancestor). The time and place of living for this inferred person can give insights in human evolutionary history. Demographic processes are incorporated in the model, but since culture and customs are known to influence demography the models used ought to be tested against available genealogy. The Icelandic data base offers a possibility to do so and points to some discrepancies. Mitochondrial DNA and Y chromosome patterns give a rather consistent view of human evolutionary history during the latest 100 000 years but the earlier epochs of human evolution demand gene trees with longer branches. The results of such studies reveal as yet unsolved problems about the sources of our genome.

Cohort Study of Opportunity for Selection on Two Swedish 19th Century Parishes with a Survey of Other Estimates

Two Swedish parishes, Fleninge in the county of Malmöhus and Nedertorneå in the county of Norrbotten, have been compared for differences in opportunity for selection. The material has consisted of demographic data from the 19th century. Both components of the index, estimated from mortality and fertility differences respectively, are high in comparison to other available estimates, and the index for Nedertorneå is higher than that of Fleninge.

ALLERGIC REACTION PATTERNS IN RELATION TO AGE, SEX, SEASON, EOSINOPHILIA AND SOME GENETIC MARKER SYSTEMS

T h e present investigation is based on data which were collected during the years 1958 to 1964. They concern 4.685 subjects tested at the Department of Clinical Chemistry, Danderyds Hospital, Sweden. The subjects had been submitted to tests from different departments of the hospital, mostly the oto-rhinolaryngological department, and on different indications, viz: i) clinically manifested allergy; 2) suspicion of allergy; 3) clinical symptoms where allergy could not be excluded. The sample is thus a mixture of people with and without allerg ic reactions, but with a much higher incidence of allergy than the general population. With age divided on 11 classes the distribution of the total material as to age a n d sex is shown in Table i. Women are oveirepresented in the material, and the age distribution is different for males and females. Compared with the age distribution in the general Swedish population ages below 10 years and above 50 years are underrepresented, all ages in between are in excess.

Old and new ideas about genes and behaviour

Genetic factors have long been recognized as contributors to variantion in behaviour both within the normal span and as mental diseases. The first attempts to make behaviour the subject of scientific genetic studies used likeness between twins and other relatives to confirm heredity. Later heritability has been used as a quantitative estimate of the genetic part of the variance. Attempts to localize genetic factors became possible when associations between phenotypic aberrations and karyotype were observed. Inborn errors of metabolism further confirmed that specific metabolic deficits could influence behaviour. Many kinds of common mental deficiencies such as senile dementia have a heterogeneous background, and so have normal variations in talents and personality. The mapping of the human genome, the availability of an unlimited number of genetic markers and efficient statistical tools promised ample discoveries of genes behind the variation. The expectations have not been fulfilled and more subtle influences on gene expression have to be assumed. Topics that are taken up include genomic imprinting, brain activation patterns, the importance of neurotransmitter regulation and non-additive interactions between genes and environment.

A case of abnormal sex-dimorphism for bristle number in Drosophila melanogaster

A line of Drosophila melanogaster with average male sternopleural bristle number higher than that of females was obtained after many generations of disruptive selection, where males with high bristle score were mated to females with low scores. This abnormal sex-dimorphism did not influence other bristle traits. Dose compensation mechanisms were not involved, and by means of chromosome substitutions it could be shown that both X-linked and autosomal loci contributed to the sex-dimorphism.

Variability in Experimental Populations of Drosophila Melanogaster with a Record of Artificial Selection

The dynamics of quantitative polygenic variation under the influence of systems of mating, selection, mutation, and random genetic drift has recently been theoretically formalized by Lande in a series of papers on phenotypic evolution, and he has devised statistical tests for the hypothesis of phenotypic change by random genetic drift or selection (Lande, 1976; 1977).

Trends in genetics – before the molecular era

Molecular techniques and biochemical questions came to dominate genetic research during the later half of the 1900th century. This does not mean that earlier achievements have lost their importance. In this review the trends in classic genetics are followed from the beginning in 1900 until the molecular aspects took over, and it is shown how they form the basis for many trains of thought in present day genetics.

Distribution of ABO genes in southeast Sweden

ABO blood group data from about 78,000 conscripts born 1900-1935 in Southeast Sweden have been analyzed for regional differentiation using a hierarchical subdivision of the area. Heterogeneity was present at all levels of division. Gene diversity among subpopulations has been compared to a corresponding estimate performed on data from the country of Västerbotten in northern Sweden.