Genome-wide inbreeding estimation within Lebanese communities using SNP arrays

Abstract

Consanguineous marriages have been widely practiced in several global communities with varying rates depending on religion, culture, and geography. In consanguineous marriages, parents pass to their children autozygous segments known as homozygous by descent segments. In this study, single-nucleotide polymorphisms were analyzed in 165 unrelated Lebanese people from Greek Orthodox, Maronite, Shiite and Sunni communities. Runs of homozygosity, total inbreeding levels, remote consanguinity, and population admixture and structure were estimated. The inbreeding coefficient value was estimated to be 1.61% in offspring of unrelated parents over three generations and 8.33% in offspring of first cousins. From these values, remote consanguinity values, resulting from genetic drift or recurrent consanguineous unions, were estimated in offspring of unrelated and first-cousin parents to be 0.61 and 1.2%, respectively. This remote consanguinity value suggests that for any unrelated marriages in Lebanon, the mates could be related as third cousins or as second cousins once removed. Under the assumption that 25% of marriages occur between first cousins, the mean inbreeding value of 2.3% may explain the increased incidence of recessive disease in offspring. Our analysis reveals a common ancestral population in the four Lebanese communities we studied.

First molecular study in Lebanese patients with Cockayne syndrome and report of a novel mutation in ERCC8 gene

“…In fact, consanguineous marriages and same-religion marriages are widely practiced in the Middle East region and particularly in Lebanon where the population is divided into different religious groups. Jalkh et al , showed a high prevalence of rare recessive diseases in offspring of related and unrelated couples in Lebanon, which is concordant with the data presented in our study [ 21 ].…”

Human inbreeding has decreased in time through the Holocene

“…This result is consistent with documented cultural preferences for first-cousin matings in some contemporary societies. 60,61 This raises the question of whether the differential rates of consanguinity among present-day Central versus West Eurasia could be traced back in time. In fact, we observed an excess of individuals with F ROH > 0.0117 in Central versus West Eurasia among ''advanced complex agriculturalists,'' roughly spanning third to first millennium BC, depending on region (odds ratio = 5.1, p = 0.009; Table 1; Data S1C).…”

Endogamy, Consanguinity and the Health Implications of Changing Marital Choices in the Uk Pakistani Community

“…In addition, a detailed family tree was drawn up by the trained interviewer. It is important to note that in highly consanguineous populations, such as the UK Pakistani community, genomic studies have shown that even couples who declare themselves to be unrelated are homozygous at a proportion of gene loci, due to consanguineous unions in ancestral generations (Jalkh et al, 2015).…”