Zygosity Diagnosis of Twins by Questionnaire

Ooki, Syuichi; Yamada, K.; Asaka, Akio; Hayakawa, Kayoko

doi:10.1017/s0001566000005626

Cited by 136 publications

(70 citation statements)

References 8 publications

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“…The participants’ age ranged from 19 to 75 years ( M =32.76, SD =6.99). Zygosity was determined based on standard items about physical similarity, a procedure with high (at least 95%) concurrence with DNA typing 36 .…”

Section: Methodsmentioning

confidence: 99%

Overlapping Genetic and Environmental Influences on Nonsuicidal Self-injury and Suicidal Ideation

et al. 2014

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Section: Methodsmentioning

confidence: 99%

Overlapping Genetic and Environmental Influences on Nonsuicidal Self-injury and Suicidal Ideation

et al. 2014

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“…Participants were aged between 27 and 40 years (mean±S.D=31.9±2.5) and the sample included 571 identical (monozygotic; MZ), 653 non-identical (dizygotic; DZ) twin pairs, and 889 single twins (where only one twin of the pair participated). The zygosity of the twin pairs was determined based on responses to standard items about physical similarity, a procedure that has been found to have at least 95% concurrence with DNA typing (Ooki et al, 1990). For further details about the recruitment procedure and other study characteristics, see Lynskey et al (2012).…”

Section: Methodsmentioning

confidence: 99%

Is the relationship between early-onset cannabis use and educational attainment causal or due to common liability?

Verweij

Huizink

Agrawal

et al. 2013

Drug and Alcohol Dependence

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Background Several studies have shown that early cannabis use is correlated with poor educational performance including high school drop-out. The predominant explanation for this relationship is that cannabis use causes disengagement from education. Another explanation is that the association between early cannabis use and educational attainment is not causal, but the result of overlapping risk factors that increase the likelihood of both early cannabis use and disengagement from education. These confounding factors could be of genetic and/or environmental origin. Methods Here we use data from a large community-based sample of adult twins (N=3337) who completed a comprehensive semi-structured telephone interview. We first apply the classical twin-design to determine whether genetic and/or environmental influences underlie the relationship between early-onset cannabis use (prior to age 18) and early school leaving. Next, with a co-twin control design we investigate whether the relationship between the two variables is more likely due to direct causality or overlapping risk factors. Results We find a significant phenotypic correlation between early-onset cannabis use and early school leaving (r=0.26), which could be explained by familial influences (of genetic and/or shared environmental origin). The pattern of odds ratios found in the co-twin control design is not consistent with direct causation, but rather suggests that the association is due to shared environmental factors influencing both variables. Conclusion Our findings suggest that the relationship between early-onset cannabis use and school leaving is due to shared environmental risk factors influencing both the risk of early-onset cannabis use and early school leaving.

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“…If so, the accuracy of classification is likely to improve with i ncreasi ng age of the parti ci pants. A few studi es have reported on thi s i ssue by eval uati ng the preci si on of zygosi ty di agnosi s betw een sampl es varyi ng i n age, 8,19,23 and by test-retest esti mati on. 9 Wi th the excepti on of the study of Cohen et al, 9 the fi ndi ngs are suggesti ve of an i ncreased preci si on i n zygosi ty predi cti on for ol der parti ci pants.…”

Section: Introductionmentioning

confidence: 99%

Zygosity diagnosis in young twins by parental report

Rietveld¹,

et al. 2000

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Thi s study r epor ts on zygosi ty deter mi nati on i n tw i ns of chi l dhood age. Par ents r esponded to questionnaire items dealing with twin similarity in physical characteristics and frequency of mi stak i ng one tw i n for another by par ents, r el ati ves and str anger s. The accur acy of zygosi ty di agnosi s w as eval uated acr oss tw i ns aged 6, 8, and 10 and acr oss par ents. I n addi ti on, i t w as exami ned w hether the use of mul ti pl e r ater s and the use of l ongi tudi nal data l ead to an i mpr ovement of zygosi ty assi gnment. Compl ete data on zygosi ty questi ons and on geneti c mar k er s or bl ood pr ofi l es w er e avai l abl e for 618 tw i n pai r s at the age of 6 year s. The method used w as pr edi cti ve di scr i mi nant anal yses. A gr eement betw een zygosi ty assi gned by the r epl i es to the questi ons and zygosi ty deter mi ned by DNA mar k er s/bl ood typi ng w as ar ound 93%. The accur acy of assi gnment r emai ned constant acr oss age and par ents. A nal yses of data pr ovi ded by both par ents and col l ected over mul ti pl e ages di d not r esul t i n better pr edi cti on of zygosi ty. Detai l s on the di scr i mi nant functi on ar e pr ovi ded. Twin Research (2000) 3, 134-141. Keyw or ds: tw i n zygosi ty, chi l dhood, questi onnai re, revi ew, di scri mi nant anal ysi s I ntr oducti onIn 1927, Si emens 1 suggested that the di agnosi s of zygosi ty i n tw i ns can take pl ace by eval uati ng the degree of resembl ance on geneti cal l y determi ned trai ts. Devel opment of thi s method resul ted i n the frequent use of questi onnai res, often i ncl udi ng those cri teri a ori gi nal l y proposed by Si emens, for exampl e.2 Several studi es have show n that the establ i shment of zygosi ty based on mai l ed questi onnai res i s of consi derabl e accuracy, w i th around 95% correctl y cl assi fi ed compared w i th bl ood or DNA typi ng. Studi es on the di agnosi s of zygosi ty by mai l ed questi onnai res are summari sed i n A ppendi x 1.

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Zygosity Diagnosis of Twins by Questionnaire

Cited by 136 publications

References 8 publications

Overlapping Genetic and Environmental Influences on Nonsuicidal Self-injury and Suicidal Ideation

Overlapping Genetic and Environmental Influences on Nonsuicidal Self-injury and Suicidal Ideation

Is the relationship between early-onset cannabis use and educational attainment causal or due to common liability?

Zygosity diagnosis in young twins by parental report

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