Processes for calculating phased fetal genomic sequences
View Patent ↗The present invention provides processes for calculating phased genomic sequences of the fetal genome using fetal DNA obtained from a maternal sample. The processes and systems of the present invention utilize novel technological and computational approaches to detect fetal genomic sequences and determine the phased heritable genomic sequences. The invention could be used, e.g., to identify in utero deleterious mutations carried by the parents and inherited by a fetus within a particular heritable genomic region.
1. A process for determining the phased composition in a fetal heritable genomic region from a maternal sample comprising maternal DNA and fetal DNA, the process comprising the steps of:
isolating cell-free nucleic acids from the maternal sample comprising the maternal DNA and the fetal DNA, wherein the cell-free nucleic acids comprise selected nucleic acid regions;
interrogating the selected nucleic acid regions in the fetal heritable genomic region using oligonucleotides to amplify the selected nucleic acid regions, the oligonucleotides comprising universal amplification sequences;
applying the amplified selected nucleic acid regions to an array-based pull-out detection system to identify informative loci corresponding to a heritable genomic region of interest;
providing, to a computer processor, phased sequence information from at least one corresponding parental heritable genomic region;
identifying, by the computer processor, five or more informative loci in the fetal DNA corresponding to a heritable genomic region of interest from the phased sequence information of the at least one corresponding parental heritable genomic region;
calculating, by the computer processor, a paternal contribution of the heritable genomic region of interest using the phased sequence information of the five or more informative loci;
calculating, by the computer processor, the maternal contribution of the heritable genomic region of interest by comparing the paternal contribution of the heritable genomic region of interest to the selected nucleic acid regions in the fetal heritable genomic region; and
generating, by the computer processor, a prediction of a likely phased composition of the heritable genomic region of interest in the fetal DNA using the maternal and paternal contributions of the heritable genomic region of interest.
2. The process of claim 1 , wherein the maternal sample is a cell free maternal sample.
3. The process of claim 2 , wherein the cell free maternal sample is maternal plasma or serum.
4. The process of claim 1 , wherein the maternal sample comprises fetal cells.
5. The process of claim 1 , wherein a fetal genetic variation within the heritable genomic region is imputed from a subset of parental informative loci.
6. The process of claim 1 , wherein the phased sequence information of the heritable genomic region is determined by sequencing of the parental genome.
7. The process of claim 1 , wherein the phased sequence information of the corresponding parental heritable genomic region is determined by pedigree analysis.
8. The process of claim 1 , wherein the phased composition in the fetal heritable genomic region comprises sequence information on at least twenty informative loci in the heritable genomic region.
9. The process of claim 1 , wherein the phased composition in the fetal heritable genomic region comprises sequence information on at least fifty informative loci in the heritable genomic region.
10. The process of claim 1 , wherein the phased composition in the fetal heritable genomic region comprises sequence information on at least one hundred informative loci in the heritable genomic region.
11. The process of claim 1 , wherein the heritable genomic region comprises a sub-chromosomal unit.
12. The process of claim 1 , wherein the heritable genomic region comprises an entire chromosome.
13. The process of claim 1 , wherein the heritable genomic region comprises the entire genome.