dizygotic twins


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Related to dizygotic twins: fraternal twins, Monozygotic twins

dizygotic twins

[¦dī·zī′gäd·ik ′twinz]
(biology)
Twins derived from two eggs. Also known as fraternal twins.
References in periodicals archive ?
Data Source: A population-based twin study involving 54 monozygotic and 138 dizygotic twin pairs born in 1987-2004 in which at least one of the twins met the diagnostic criteria for autism or autism spectrum disorder.
When ultrasonography reveals the absence of a "twin-peak sign" indicating a monochorionic placenta, the twins are most likely monozygotic; however, a dichorionic diamniotic (DCDA) [4] placenta--as evidenced by the presence of a twin-peak sign and the same sex for both fetuses--is observed in at least 40% of all twin pregnancies and is compatible with both monozygotic and dizygotic twins.
Our method is safer than amniocentesis, and it is more conclusive than ultrasound scanning, which can present both monozygotic and dizygotic twins as DCDA twins.
Besides the capability to assess chromosomal aneuploidy, the ability to measure the fetal DNA contributions of individual fetuses of dizygotic twins could serve as a useful internal positive control for any tests based on analyzing circulating fetal DNA in maternal plasma for these pregnancies, such as noninvasive fetal RHD genotyping (26) and single-gene disease diagnosis (13, 27, 28).
In addition to serving as a guide to or an internal control for the interpretation of prenatal genetic tests, the ability to measure the DNA contribution of an individual fetus of dizygotic twins might also allow one to monitor the well-being of each twin.
FRACTIONAL FETAL DNA CONCENTRATIONS OF MEMBERS OF DIZYGOTIC TWINS
On the other hand, dizygotic twins are genetically nonidentical.
We compared these proportions for the monozygotic and dizygotic twins.
Next, we determined the fractional fetal DNA concentration for each fetus of pregnancies that showed regional variations in apparent fetal DNA concentrations and hence that we suspected of carrying dizygotic twins.
Monozygotic twins should be identical in their genetic makeup across the entire genome, whereas dizygotic twins are not genetically identical.
Fractional fetal DNA concentration of member of a dizygotic twin pair resolved by the binomial-mixture model or by use of informative SNP sites confirmed by microarray genotyping.
Examining differences in the levels and activity states of these components within pairs of monozygotic and dizygotic twins, the Stanford scientists found that in three-quarters of the measurements, nonheritable influences -- such as previous microbial or toxic exposures, vaccinations, diet and dental hygiene -- trumped heritable ones when it came to accounting for differences within a pair of twins.