twin

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Related to monozygotic: Monozygotic twins

twin

1. 
a. either of two persons or animals conceived at the same time
b. (as modifier): a twin brother
2. a crystal consisting of two parts each of which has a definite orientation to the other
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

twin

[′twin]
(biology)
One of two individuals born at the same time.
(crystallography)
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
These results indicate that the monozygotic twin rugae patterns are not identical with each other and their differences are greater than individual changes seen in the reference group over time [10, 11].
This study compared N400 semantic priming effects across a sample of monozygotic twins concordant and discordant for schizophrenia and healthy monozygotic twins and found significant differences between the groups only on the N400 priming effect for the direct condition.
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.
The direct influence of V[O.sub.2]max on PPARG expression has not been previously examined, regardless of genetic background, but it can be evaluated using the discordant monozygotic (MZ) twin model (cotwin case control study design).
Studying a pair of identical (monozygotic) twins, one affected and one unaffected with Parkinson's disease, another unrelated Parkinson's patient, and four healthy control subjects, the scientists were able to observe key features of the disease in the laboratory.
Studying a pair of identical (monozygotic) twins, one affected and one unaffected with Parkinson's disease, another unrelated Parkinson's patient, and four healthy control subjects, the scientists were able to observe key features of the disease in the laboratory, specifically differences in the patients' neurons' ability to produce dopamine, the molecule that is deficient in Parkinson's disease.
They discuss media and embryo interactions, the female tract environment, buffering systems, essential features in media development, macromolecular supplementation of embryo culture media, monozygotic twinning, amino acids and ammonium, growth factors and cytokines, osmolality, pH control, oocyte maturation in vitro, oocyte and embryo cryopreservation, and regulatory matters, as well as the culture of embryos in dynamic fluid environments, morphokinetic analysis using time-lapse imaging of embryo development, optimizing culture conditions, low cost in vitro fertilization, incubators, and incubator management.
This study also concluded that in monozygotic twins, concordance for idiopathic scoliosis is much higher than in same sex dizygotic twins.
Twinning can range from incomplete bilateral forms such as cyclopia, through various grades of supernormal forms such as double headed types, double monsters and conjoined twins, culminating in completely separate monozygotic or duplicate twins.
Doctors said that the condition is usually found in monozygotic twins ( originating from the same fertilised ovum) but what made the surgery critical were the rare blood group the two babies shared and the need for extensive cranial re- modelling.
(1) In addition to being matched on typical characteristics such as age or race, twins are by design matched in varying degrees on genetic propensity: monozygotic (MZ) twins share 100% of their genetic makeup and dizygotic (DZ) twins share on average 50%.