Linkage analysis in a large family from Pakistan with depression and a high incidence of consanguineous marriages

Homozygosity mapping of depressive disorder in a large family from Pakistan: significant linkage on chromosome 6 and 9

A large family with a high prevalence of recurrent major depression and high average inbreeding coefficient was ascertained from rural Pakistan. Subjects were interviewed and diagnosed by a trained psychiatrist, 370 microsatellite markers were genotyped and the program FEstim was used for homozygosity mapping. Significant linkage was found on Chromosome 9 and Chromosome 6 after fine mapping. These regions on Chromosome 6 and 9 may harbor genes which predispose to depression.

Legacy of mutiny on the Bounty: founder effect and admixture on Norfolk Island

The population of Norfolk Island, located off the eastern coast of Australia, possesses an unusual and fascinating history. Most present-day islanders are related to a small number of the 'Bounty' mutineer founders. These founders consisted of Caucasian males and Polynesian females and led to an admixed present-day population. By examining a single large pedigree of 5742 individuals, spanning >200 years, we analyzed the influence of admixture and founder effect on various cardiovascular disease (CVD)-related traits. On account of the relative isolation of the population, on average one-third of the genomes of present-day islanders (single large pedigree individuals) is derived from 17 initial founders. The proportion of Polynesian ancestry in the present-day individuals was found to significantly influence total triglycerides, body mass index, systolic blood pressure and diastolic blood pressure. For various cholesterol traits, the influence of ancestry was less marked but overall the direction of effect for all CVD-related traits was consistent with Polynesian ancestry conferring greater CVD risk. Marker-derived homozygosity was computed and agreed with measures of inbreeding derived from pedigree information. Founder effect (inbreeding and marker-derived homozygosity) significantly influenced height. In conclusion, both founder effect and extreme admixture have substantially influenced the genetic architecture of a variety of CVD-related traits in this population.