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Zygosity Testing: Laboratory and the Investigator's Judgment

Published online by Cambridge University Press:  01 August 2014

Nancy L. Segal*
Affiliation:
Department of Psychology, University of Minnesota, Minneapolis
*
University of Minnesota, Department of Psychology, Minneapolis, MN 55455, USA

Abstract

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The immediate global impressions of zygosity (based upon physical similarity) were recorded by the investigator at initial meetings with 105 pairs of twins. The accuracy of these ratings, as well as classifications provided by two objective procedures (physical resemblance questionnaire; dermatoglyphic analyses) and two subjective procedures (parental impressions; physician's impressions), were evaluated by comparison with results from bloodtyping for 53 pairs. The judgments of the investigator furnished the most accurate indication of zygosity (94-96% accuracy). Laboratory tests were repeated for five pairs when the results proved incompatible with the investigator's ratings. In all five cases, the investigator's judgments were confirmed, indicating that a laboratory error had occurred. It appears that the opinion of a skilled observer of twins can provide a convenient and highly effective alternative to bloodtyping.

Type
Research Article
Copyright
Copyright © The International Society for Twin Studies 1984

References

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