Chromosomal and other genetic polymorphisms in a County Durham population

Abstract

Chromosomal polymorphisms detected with the stain quinacrine dihydrochloride have been examined in a sample of people resident in County Durham. Attempts have been made to correlate the frequencies of these polymorphisms with certain demographic variables, information about which was collected from the participants using questionnaires. Other genetic markers, detectable from blood samples, have also been studied, with a view to comparing the patterns of variability shown by these in the population, with those of the less well studied chromosome variants. Demoaraphic information was collected from each person concerning his or her age, sex, occupation and geographic origins. Parental ages and birth order data were also collected in the case of newborn infants. No consistent correlations were observed between any of the chromosome variants and any of the demographic factors. However, there were indications of an association of the total number of variants found per individual karyotype with sex and with age. The results obtained in this study have been compared with those of published reports of chromosome variability. The conclusion drawn from this comparison is that, although there is evidence that a degree of similarity of frequency exists between populations, the extent of such similarity is extremely difficult to quantify objectively. Information concerning the molecular nature of chromosomes, and their polymorphisms, has been reviewed with the intention of revealing any theoretical basis there may be for an adaptive significance of the variants. The incidence of other chromosomal variations in human populations has also been described, in order to detect any evidence that may exist for a biological or evolutionary significance of any type of chromosomal variability. NO compelling evidence has been found to indicate that Chromosomal polymorphisms have an adaptive importance in present-day human populations, nor has any information which would indicate a theoretical basis for such an observation.