Reliably Separating Identical From Fraternal Twins

Cohen, Donald J.

doi:10.1001/archpsyc.1975.01760290039004

Cited by 192 publications

(135 citation statements)

References 6 publications

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“…= 5 months; Range= 0.8 to 25 months) after initial contact. Zygosity was assessed by maternal report of physical similarity (Cohen et al, 1975). Total data were available for 2648 individuals.…”

Section: Methods Participantsmentioning

confidence: 99%

Parental punitive discipline, negative life events and gene–environment interplay in the development of externalizing behavior

et al. 2007

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Section: Methods Participantsmentioning

confidence: 99%

Parental punitive discipline, negative life events and gene–environment interplay in the development of externalizing behavior

et al. 2007

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“…20 Table 1 shows the number of monozygotic (MZ), dizygotic (DZ) and sibling individuals as well as the number of full pairs for each variable.…”

Section: Participantsmentioning

confidence: 99%

A Longitudinal Twin and Sibling Study of Associations between Insomnia and Depression Symptoms in Young Adults

Gregory

Rijsdijk

Eley

et al. 2016

Sleep

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Study Objectives: To estimate genetic and environmental influences on the associations between insomnia and depression symptoms concurrently and longitudinally. Methods: Behavioral genetic analyses were conducted on data from the British longitudinal G1219 twin/sibling study. One thousand five hundred fiftysix twins and siblings participated at Time 1 (mean age = 20.3 years, SD = 1.76). Eight hundred sixty-two participated at Time 2 (mean age = 25.2 years, SD = 1.73 years). Participants completed the Insomnia Symptoms Questionnaire and the Short Mood and Feelings Questionnaire to assess symptoms of insomnia and depression respectively. Results: Genetic effects accounted for 33% to 41% of the variance of the phenotypes. The phenotypic correlations were moderate (r = 0.34 to r = 0.52). The genetic correlations between the variables were high (0.73-1.00). Genetic effects accounted for a substantial proportion of the associations between variables (50% to 90%). Non-shared environmental effects explained the rest of the variance and covariance of the traits. Conclusions: While genetic effects play a modest role in insomnia and depression symptoms separately, they appear to play a more central role in concurrent and longitudinal associations between these phenotypes. This should be acknowledged in theories explaining these common associations.

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“…The Biographical Questionnaire included the 5 questions listed in Table 1, very similar to those employed by prior authors [9,10,35] in achieving an accuracy of some 95% in zygosity diagnosis. Since 74 pairs of Registry twins had participated in an earlier laboratory study, for which their zygosity was established by elaborate serological analysis [25], it was possible to validate our questionnaire method for these 148 individuals.…”

Section: Zygosity Determinationmentioning

confidence: 99%

The Minnesota Twin Family Registry: Some Initial Findings

Lykken

Bouchard

McGue

et al. 1990

Acta genet. med. gemellol.: twin res.

299

192

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Abstract. A birth-record based Registry is nearing completion of some 8,000 pairs of twins born in Minnesota from 1936 to 1955, plus some 1,200 pairs of male twins born 1971-81. The middle-aged twins were recruited with graded incentives so that ease of recruitment could be measured; it was found that pairs concordant for ease of recruitment were no more similar than discordant pairs in education, socioeconomic status (SES), or a variety of personality and interest factors, ie, that selection bias may not be a problem in research with adult twins when contacts are only by mail. A 50% decrease in neonatal mortality from 1936-55 to 1971-81 was associated with an increase from 3.5 to 4.0 per thousand in the frequency of viable MZ twin births. The broad heritability of SES, educational attainment, fecundity, and risk for divorce ranges from 0.30 to 0.50, although all 4 variables are plainly multifactorial and the latter 2 both involve variance contributed by a second person. Investigators interested in making use of this research resource are invited to submit proposals.

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Reliably Separating Identical From Fraternal Twins

Cited by 192 publications

References 6 publications

Parental punitive discipline, negative life events and gene–environment interplay in the development of externalizing behavior

Parental punitive discipline, negative life events and gene–environment interplay in the development of externalizing behavior

A Longitudinal Twin and Sibling Study of Associations between Insomnia and Depression Symptoms in Young Adults

The Minnesota Twin Family Registry: Some Initial Findings

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