How to determine homozygous and heterozygous SNP within a genotype

Question

[Bioinfonext]

I am trying to understand how can be read a particular locus on both chromosomes when we do sequencing, and calling a particular SNP homozygous or heterozygous.

Like for SNP detection within a DNA againt the reference sequence:

1) We are doing fragmentation of DNA 2) Ligation of adapter and bar code 3) PCR 4) Denaturation 5) Sequencing

So how we can determine that both chromosome segments were sequenced for a particular locus?

Answer 1

[2nelly]

The whole procedure is unbiased. it s practically impossible to sequence only the one allele if you have a good coverage