Determining the sex of the fetus from plasma of the pregnant mother

Question

[charizanisk]

So many people have mentioned previously about seeing reads aligned in the Y chromosome when the sequencing data is from a female subject. So there are ways around it, such as masking PAR regions or excluding the Y chromosome from the study completely.

I have the following challenge. What can you do when you use plasma from a pregnant mom, you don't know the gender of the fetus and you are trying to determine:

a) the fraction of the fetal circulating DNA

b) the gender of the fetus

We get reads on the Y chromosome (in non-PAR regions) and we can't predict the gender.

We got the best results by using the old Bowtie version with couple options to align our data, but still can't clearly tell if the fetus is a male or female.

[karl.stamm]

There's a lot of work commercially in this space. Take a look at the noninvasive prenatal tests for trisomy, they're closely related to your question.

[charizanisk]

Thank you Karl,

All the papers that I have seen out there use both maternal and paternal fgenotypes and use only parental-specific homozygous loci to determine the fetal DNA fraction and do the rest of the analysis. My problem is that we don't have the paternal genotype... aka we are fishing in the dark.