dizygotic twins


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Related to dizygotic twins: fraternal twins, Monozygotic twins

di·zy·got·ic twins

twins derived from two zygotes.

dizygotic twins

two offspring born of the same pregnancy and developed from two ova that were released from the ovary simultaneously and fertilized at the same time. They may be of the same or opposite sex, differ both physically and genetically, and have two separate and distinct placentas and membranes, both amnion and chorion. The frequency of dizygotic twinning varies according to ethnic origin (the highest incidence occurs in African-Americans, the lowest in Asian-Americans, with Caucasians intermediate), maternal age (the highest rate occurs when the mother is 35 to 39 years of age), and heredity (showing an increase in the female genetic line rather than the male, although fathers may transmit the disposition to double ovulation to their daughters). In general the overall ratio is two thirds dizygotic twinning to one third monozygotic. Also called binovular twins, dissimilar twins, false twins, fraternal twins, heterologous twins.
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Development of dizygotic twins

dizygotic twins

Fraternal twins Twins resulting from 2 separate fertilized eggs, liberated simultaneously from the ovaries, which develop in separate or partially fused chorion and placenta, and usually a separate amniotic sac. Cf Monozygotic twins.

di·zy·got·ic twins

(dī-zī-got'ik twinz)
Twins derived from two zygotes.
Synonym(s): fraternal twins, heterologous twins.

dizygotic twins

or

fraternal twins

a pair of children born at the same time to the same mother but each developing from a different fertilized egg. Such twins are therefore nonidentical, being equivalent to normal SIBLINGS, and can be of the same or different sexes. Compare MONOZYGOTIC TWINS.
References in periodicals archive ?
The probability that a dizygotic twin with IBS would have a mother with IBS was greater than the chance that the twin would have a cotwin with IBS (Gastroenterology 121[4]:799-804, 2001).
Our findings argue for a hereditary component of pyloric stenosis: (1) pre-dominance in boys; (2) familial aggre-gation in first-, second-, and third-degree relatives; (3) high concordance rate in monozygotic twins; (4) similar degree of aggregation in dizygotic twins and siblings; (5) difference in risk for siblings vs.
If the similarity is found to be greater among monozygotic than dizygotic twins, genetic factors play a role in the characteristic under investigation.
Morphological features such as the Carabelli's trait were found to have higher concordance in MZ twins than in dizygotic twins [Biggerstaff, 1973; Boraas et al.
In studies of male twins, monozygotic twins (single egg) are more likely than are dizygotic twins (two eggs fertilized by two different sperm) to be concordant for homosexuality.
The investigation involved more than 4,000 monozygotic and dizygotic twins, aged 22-27 years (average age 25), who were enrolled in a population-based longitudinal twin study.
In fact, they found coronary flow rate was significantly lower in dizygotic twins with a history of major depression compared to their fraternal twins without major depression, but there was no significant flow rate difference between monozygotic twins discordant for the disorder.
In monozygotic twins, only one placenta is present; consequently, the risk of death of one twin is higher than in dizygotic twins, where two placentas are present.
The risk of disease in siblings of RA patients compared with that of the general population (Xs) is estimated as 2-17 and the concordance rates for monozygotic twins versus dizygotic twins range between 15% and 3.
For ASD, probandwise concordance for monozygotic twins was 77% for 45 male pairs and 50% for 9 female pairs; however, concordance rates for dizygotic twins were 31% for 45 male pairs and 36% for 13 female pairs.
MAKE TWO Non-identical or dizygotic twins occur when two fertilized eggs are implanted in the uterus wall at the same time.
If the risk for alcoholism, at least in part, results from genetic factors, one would expect monozygotic twins, who have identical genomes, to have a higher concordance rate for alcohol dependence than dizygotic twins, who on average only share one-half of their genomes.