Patent ID: 8949036
Filing Date: 2015-02-03
Classification: C12Q,G16B,G16H

Abstract:
1. A method for determining the number of copies of a chromosome or chromosome segment of interest in the genome of at least one gestating fetus, the method comprising: measuring the quantity of one or more alleles at a plurality of polymorphic loci on at least one chromosome in a plurality of mixed samples from a plurality of pregnant mothers; wherein each mixed sample comprises DNA from a fetus and DNA from the mother of the fetus; using the measured quantities of the alleles to determine the ratio of fetal to maternal DNA in each of the mixed samples; dividing the mixed samples into different subsets based on the ratio of fetal to maternal DNA in each of the mixed sample comprising a first subset with at least one mixed sample that has a larger ratio of fetal to maternal DNA and a second subset with at least one mixed sample that has a smaller ratio of fetal to maternal DNA; sequencing a first amount of DNA molecules in at least one mixed sample in the first subset to obtain a measured genetic data at a plurality of loci on a chromosome or chromosome segment of interest; sequencing a second amount of DNA molecules in at least one mixed sample in the second subset to obtain measured genetic data at a plurality of loci on a chromosome or chromosome segment of interest; wherein the second amount of DNA molecules is larger than the first amount of DNA molecules; creating a plurality of hypotheses specifying the number of copies of the chromosome or chromosome segment of interest in the genome of at least one of the fetuses; determining, on a computer, the probability of each of the hypotheses using the measured genetic data; and selecting the hypothesis with the greatest probability, thereby determining the number of copies of the chromosome or chromosome segment of interest in the genome of at least one of the fetuses.