Abstract: The present invention relates to the field of biotechnology. A method and system of detecting fetal chromosomal abnormalities are disclosed.

Abstract: Provided is a base mutation detection method, which includes: determining an initial frequency of sequencing data of samples being a specific base at an interested locus; calculating, based on the initial frequency, an expected value of each sample being the specific base at the interested locus; updating the initial frequency of the sequencing data of the samples being the specific base at the interested locus; further calculating the expected value of each sample being the specific base at the interested locus, further updating the initial frequency of the sequencing data of the samples being the specific base at the interested locus, and repeating the foregoing iteration until the expected value of each sample being the specific base at the interested locus converges; and determining, based on each converging expected value, a base mutation type and a mutation confidence at the interested locus of each sample.

Abstract: Provided is a method and system of reconstructing a haplotype of a diploid. The method can include constructing a matrix of sequence fragments consisting of ternary character based on sequence fragments comprising at least one common site, wherein in the matrix of sequence fragments, two allelic bases of an SNP site in chromosome fragments are labeled with A and B respectively; initializing two fragment sets of based on the matrix of sequence fragments; determining an objective function and an initial reference temperature; performing a process of simulated annealing based on the objective function and the initial reference temperature, and outputting final sets until a convergence criteria is achieved; inferring a haplotype based on the final sets by means of minimum error correction.