Determination of haploid DNA sequences in humans: application to the glucocerebrosidase pseudogene.
Variation analyses in the human genome at the sequence level, especially human genetic population analysis and genetic epidemiology, are hampered by the difficulty to ascertain haplotypes on autosomal regions. We have designed a new methodological approach to obtain autosomal haploid sequences from diploid organisms. First, genotypes are unambiguously determined through long-range PCR and diploid DNA sequencing. Second, cloning the whole PCR-amplified segment and sequencing a single clone for those fragments that presented a heterozygous position discern the allelic phase. The second allele is deduced from the genotype, and the phase reconfirmed by sequencing a second clone. A hundred human chromosomes were analysed for a 5.4 kb encompassing the glucocerebrosidase pseudogene on human chromosome 1. Haplotypes were unambiguously ascertained for all samples. The manner to combine the used techniques makes this approach a novelty. Haploid sequences from diploid organisms are obtained in a less time consuming and more accurate manner than in other used procedures.
Unitat de Biologia Evolutiva, Facultat de Ciències de la Salut i de la Vida, Universitat Pompeu Fabra, Doctor Aiguader 80, 08003 Barcelona, Spain.
Rosa
R
Martínez-Arias
Jaume
J
Bertranpetit
David
D
Comas
D005962:Glucosylceramidase / Q000235:genetics*; D006238:Haploidy; D006239:Haplotypes; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011544:Pseudogenes; D017422:Sequence Analysis, DNA / Q000379:methods*
D005962:Glucosylceramidase