The Irish Famine and its sequel: population structure changes in the Ards Peninsula, Co. Down, 1841-1911

Using censal data, the population structure of the Ards Peninsula, Co. Down was investigated from 1841 to 1911. During the study period there were highly significant declines at townland level in the mean total population, population density, number and proportion of inhabited houses, household size and deviations in the male/female ratio. The potential genetic effects of the changes, mediated via reduced effective population sizes, were exacerbated by marked differences in the patterns of population structure variation by religion. It is suggested that the current high incidence of recessive genetic disorders in the Northern Irish can be ascribed, at least in part, to these post-Famine events.