Twins Reunited: Scientific and Personal Perspectives/Twin Research Studies: Multiple Birth Effects on IQ and Body Size; Life Style, Muscles, and Metabolism; Monochorionic Dizygotic Twin with Blood Chimerism; Amniocentesis for Twins/Twins in the Media: Identical Doctors; Freedom Fighter for Twins; Twin Scholarships; Auguste and Jean-Felix Piccard; Twins Born Apart

The centenary celebration for Scottish missionary, Mary Slessor, took place on February 14, 2015 in Melle, Belgium. Slessor saved many newborn twins and their mothers from death and disownment by members of their community, including their families, who believed twins harbored evil spirits. The events of this unusual and significant gathering are described. Next, twin research and reports concerning Kleinfelter's disease, atopic diseases, autism and psychotherapy are presented. General interest subjects include identical female twin pole-vaulters, the longest twin birth interval, Franco-Cuban twin vocalists, and Croatian twin models.

show abstract

Utilizing the Resource of Twins Reared Apart: Their Distribution Across Nine Provinces or Cities of China

Gao

Zeng

Cao

et al. 2015

Twin Res Hum Genet

View full text Add to dashboard Cite

Twins reared apart provide a fascinating experiment to distinguish genetic from environmental influences. However, there is as yet no broad report on distribution of twins reared apart, especially in the Chinese population. In this study, information on 18,295 volunteer twin pairs of all age groups was compiled in nine provinces or cities of China, and questionnaires were used for zygosity determination. It was discovered that twins reared apart from 0 to 10 years of age accounted for 2.2% of all twin interviewees, with the proportion of this 0-10 group separated before 1, 2, and 5 years old, accounting for 65.3%, 76.1%, and 91.3%, respectively. The proportion of twins reared apart is not significantly related to zygosity or gender, but it is related to region and twin age. As the age of twins lowers, the proportion of those reared apart gradually decreases. Twins reared apart will become rarer in the future and therefore should be cherished as a resource.Keywords: twin studies, child rearing, adoption, environment, genes Classical twin design (CTD) estimates the parameters of additive genetic variance (V A ), non-additive genetic variance (V NA ), common environmental effect variance (V C ), and unique environmental effect variance (V E ) by comparing the similarities between monozygotic (MZ) twins and dizygotic (DZ) twins. Apart from these four parameters, the correlation coefficient (r) of DZ twins attributable to non-additive genetic influence is also unidentified (Coventry & Keller, 2005). However, CTD only obtains three observations: total phenotypic variance, MZ phenotypic covariance, and DZ phenotypic covariance. It is obviously impossible to deduce the five parameters from the three observations, since the degree of freedom will be negative when using structural equation models (Ozaki et al., 2011). We therefore must assume r = 1/4 and V C or V NA = 0 to estimate the three other parameters. This is a potential limitation of CTD -bias -and often occurs during parameter estimation since V C and V NA cannot be estimated simultaneously while fixing r at 1/4 (Coventry & Keller, 2005).One way to address the problem is to study twins reared apart, which is an ingenious concept and known as 'the fascinating experiment of nature, the simplest and most powerful method for disentangling the influence of

show abstract

Cited by 3 publications

References 16 publications

Good Twin–Evil Twin and Other Family Ties

Good Twin–Evil Twin and Other Family Ties

Utilizing the Resource of Twins Reared Apart: Their Distribution Across Nine Provinces or Cities of China

Contact Info

Product

Resources

About