Noninvasive genotyping of 9 Y-chromosome specific STR loci using circulatory fetal DNA in maternal plasma by multiplex PCR.
BACKGROUND
Human Y-Chromosome specific STR (Y-STR) has now become a useful loci in casework. However, noninvasive genotyping of multiple Y-STR loci and its application in prenatal genetic diagnosis haven't been reported. The purpose of this study is to develop a Y-STR multiplex PCR amplification system that is suitable for the amplification of short-sized templates of circulatory male fetal DNA and use the established multiplex in noninvasive prenatal genetic diagnosis and its further applications in forensic casework.


METHODS
On the basis of the characteristic of circulatory fetal DNA in maternal plasma, we selected 9 Y-STR loci in which the allele size was less than 180 bp in length and developed two multiplexes that allowed fluorescent genotyping of 9 Y-STR loci simultaneously. These Y-STR loci include two trinucleotide repeats (DYS426 and DYS388) and seven tetranucleotide repeats (DYS393, DYS460, H4; DYS391, DYS389 I, DYS456 and DYS458). Sixty-four pairs of plasma DNA samples from pregnant women and genomic DNA samples from their husbands were detected by our method.


RESULTS
As a result, an average of 7.3 Y-STR specific alleles was detected in each of the 30 plasma DNA samples from pregnancies with male fetuses. However, none of these 9 Y-STR specific alleles was detected in 34 plasma samples from pregnant women carrying female babies. The chances of detecting Y-STR alleles ranged from 66.7 to 93.3%. Fifty-eight haplotypes were detected in 64 unrelated Chinese male individuals; haplotype diversity was 0.9966. This highly polymorphic Y-STR multiplex has greatly improved the chances of detecting the Y-STR allele.


CONCLUSIONS
This assay provides a sensitive, accurate and efficient method for noninvasive prenatal genetic diagnosis and forensic casework.
Deng
ZhiHui
Z
Shenzhen Blood Center, Shenzhen, Guang Dong, 518035, PR of China. zhihui_deng@yahoo.com.cn
Wu
GuoGuang
G
Li
Qian
Q
Zhang
Xuan
X
Liang
YanLian
Y
Li
DaCheng
D
Gao
SuQing
S
Lan
YuXiao
Y
D000483:Alleles; D041322:Chromosomes, Human, Y / Q000235:genetics*; D004247:DNA / Q000097:blood*; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D011247:Pregnancy; D012680:Sensitivity and Specificity; D012732:Sex Determination Analysis; D020080:Tandem Repeat Sequences / Q000235:genetics*
D004247:DNA