Long contiguous stretches of homozygosity in the human genome.
Single nucleotide polymorphisms (SNPs) are the most common sequence variation in the human genome; they have been successfully used in mapping disease genes and more recently in studying population genetics and cancer genetics. In a population-based association study using high-density oligonucleotide arrays for whole-genome SNP genotyping, we discovered that in the genomes of unrelated Han Chinese, 34 out of 515 (6.6%) individuals contained long contiguous stretches of homozygosity (LCSHs), ranging in the size from 2.94 to 26.27 Mbp (10.22+/-5.95 Mbp). Four out of four (100%) Taiwan aborigines also demonstrated this genetic characteristic. The number of LCSH regions increased markedly in the offspring of consanguineous marriages. LCSH was also detected in Caucasian samples (11/42; 26.2%) and African American samples (2/42; 4.76%). A total of 26 LCSH regions were recurrently detected among Han Chinese, Taiwan aborigines, and Caucasians. DNA copy number determination by hybridization intensity analysis and real-time quantitative PCR (qPCR) excluded deletion as the cause of LCSH. Our results suggest that LCSHs are common in the human genome of the outbred population and this genetic characteristic could have a significant impact on population genetics and disease gene studies.
Li
Ling-Hui
LH
Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
Ho
Sheng-Feng
SF
Chen
Chien-Hsiun
CH
Wei
Chun-Yu
CY
Wong
Wan-Ching
WC
Li
Li-Ying
LY
Hung
Shuen-Iu
SI
Chung
Wen-Hung
WH
Pan
Wen-Han
WH
Lee
Ming-Ta M
MT
Tsai
Fuu-Jen
FJ
Chang
Ching-Fen
CF
Wu
Jer-Yuarn
JY
Chen
Yuan-Tsong
YT
D001741:Black or African American / Q000235:genetics; D044466:Asian People / Q000235:genetics; D001483:Base Sequence; D002877:Chromosomes, Human; D003241:Consanguinity; D005190:Family; D018628:Gene Dosage; D005828:Genetics, Population; D015894:Genome, Human; D006720:Homozygote; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D011995:Recombination, Genetic; D013624:Taiwan / Q000208:ethnology; D044465:White People / Q000235:genetics