Twin Differentiation of Cognitive Ability Through Phenotype to Environment Transmission: The Louisville Twin Study

Glutathione and cysteine are major antioxidants in blood that are associated with health and longevity. To ensure their measurement, careful attention to avoid auto-oxidation is necessary to stabilize the samples. Since no report of these compounds has been reported in children, our goal was to determine their levels of reduced and oxidized glutathione (GSH and GSSG) and cysteine (Cys and CSSC), To this end, 140 healthy children, ages 2 to 9 years from the Louisville Twin Study were studied. Blood samples were collected and analyzed for GSH, GSSG, Cys, and CSSC by our HPLC dual electrochemical method. The results showed that GSH and total GSH (GSH + GSSG) levels for monozygotic (MZ) twins were significantly higher (P < 0.001) than levels for dizygotic (DZ) twins. However, the opposite occurred for Cys and total Cys (Cys + CSSC) in that the levels were significantly higher for DZ twins than for MZ twins. (P < 0.005-0.013). In spite of this marked difference in zygosity, the withinpair correlations for twin pairs used for estimating heritability suggested that there was a major environmental influence for total GSH and total Cys. Finally. GSH levels were significantly lower for young (2–9 years) children than adults (P < 0.001).

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The Louisville Twin Study: Past, Present and Future

Twin Research and Human Genetics ◽

10.1017/thg.2019.37 ◽

2019 ◽

Vol 22 (6) ◽

pp. 735-740 ◽

Cited By ~ 1

Author(s):

Deborah W. Davis ◽

Eric Turkheimer ◽

Deborah Finkel ◽

Christopher Beam ◽

Lesa Ryan

Keyword(s):

Pilot Study ◽

Child Development ◽

Data Collection ◽

Twin Study ◽

Multiple Birth ◽

Face To Face ◽

Data Collection Methods ◽

Data Preservation ◽

Louisville Twin Study ◽

Collection Methods

AbstractThe Louisville Twin Study (LTS) is nationally recognized as one of the largest and most comprehensive studies of child development related to multiple birth status. The LTS is unique because of the extensive longitudinal face-to-face assessments, the frequency of data collection, the inclusion of data on additional family members (i.e., parents, siblings, grandparents; and later, twins’ own spouses and children), and the variety of data collection methods used. Data preservation efforts began in 2008 and are largely complete, although efforts are ongoing to obtain funding to convert the electronic data to a newer format. A pilot study was completed in the summer of 2018 to bring the twins, who are now middle-aged, back for testing. A grant is currently under review to extend the pilot study to include all former participants who are now ≥40 years of age. Opportunities for collaboration are welcome.

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The Louisville Twin Study: Developmental Synchronies in Behavior

Child Development ◽

10.2307/1129693 ◽

1983 ◽

Vol 54 (2) ◽

pp. 298 ◽

Cited By ~ 291

Author(s):

Ronald S. Wilson

Keyword(s):

Twin Study ◽

Louisville Twin Study

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The prediction of school achievement from a behavior genetic perspective: Results from the German twin study on Cognitive Ability, Self-Reported Motivation, and School Achievement (CoSMoS)

Personality and Individual Differences ◽

10.1016/j.paid.2012.01.020 ◽

2012 ◽

Vol 53 (4) ◽

pp. 381-386 ◽

Cited By ~ 14

Author(s):

Juliana Gottschling ◽

Marion Spengler ◽

Birgit Spinath ◽

Frank M. Spinath

Keyword(s):

Cognitive Ability ◽

Twin Study ◽

School Achievement ◽

Behavior Genetic

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Genetics of Cognition: Outline of a Collaborative Twin Study

Twin Research ◽

10.1375/twin.4.1.48 ◽

2001 ◽

Vol 4 (1) ◽

pp. 48-56 ◽

Cited By ~ 77

Author(s):

Margie Wright ◽

Eco De Geus ◽

Juko Ando ◽

Michelle Luciano ◽

Danielle Posthuma ◽

...

Keyword(s):

Working Memory ◽

Individual Differences ◽

The Netherlands ◽

Cognitive Ability ◽

Processing Speed ◽

Twin Study ◽

Memory Task ◽

Inspection Time ◽

Phenotypic Correlation ◽

Spatial Span

AbstractAmultidisciplinary collaborative study examining cognition in a large sample of twins is outlined. A common experimental protocol and design is used in The Netherlands, Australia and Japan to measure cognitive ability using traditional IQ measures (i.e., psychometric IQ), processing speed (e.g., reaction time [RT] and inspection time [IT]), and working memory (e.g., spatial span, delayed response [DR] performance). The main aim is to investigate the genetic covariation among these cognitive phenotypes in order to use the correlated biological markers in future linkage and association analyses to detect quantitativetrait loci (QTLs). We outline the study and methodology, and report results from our preliminary analyses that examines the heritability of processing speed and working memory indices, and their phenotypic correlation with IQ. Heritability of Full Scale IQ was 87% in the Netherlands, 83% in Australia, and 71% in Japan. Heritability estimates for processing speed and working memory indices ranged from 33–64%. Associations of IQ with RT and IT (−0.28 to −0.36) replicated previous findings with those of higher cognitive ability showing faster speed of processing. Similarly, significant correlations were indicated between IQ and the spatial span working memory task (storage [0.31], executive processing [0.37]) and the DR working memory task (0.25), with those of higher cognitive ability showing better memory performance. These analyses establish the heritability of the processing speed and working memory measures to be used in our collaborative twin study of cognition, and support the findings that individual differences in processing speed and working memory may underlie individual differences in psychometric IQ.

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Twin Similarity in the Developmental Transformations of Infant Temperament as Measured in a Multi-Method, Longitudinal Study

Acta geneticae medicae et gemellologiae twin research ◽

10.1017/s0001566000007212 ◽

1984 ◽

Vol 33 (2) ◽

pp. 181-189 ◽

Cited By ~ 6

Author(s):

Adam P. Matheny

Keyword(s):

Factor Analysis ◽

Twin Study ◽

Infant Temperament ◽

Social Orientation ◽

Genetic Influences ◽

Louisville Twin Study ◽

Parental Ratings ◽

Developmental Transformations ◽

Study Laboratory ◽

Temperament Dimension

AbstractIn the Louisville Twin Study, laboratory observations of twin infants' temperament at 12, 18, and 24 months were linked with parental ratings from temperament questionnaires. Core dimensions of temperament were extracted by factor analysis applied to each set of measures at each age. The laboratory temperament dimension was recurrently represented by emotional tone, social orientation, attentiveness, and reaction to restraint. The questionnaire temperament dimension was recurrently represented by mood, approach/withdrawal and adaptability. The laboratory and questionnaire dimensions were found to be correlated at each age (convergent correlations: 0.38 to 0.52) and to be stable across ages (stability correlations 0.37 to 0.66). The temperament dimensions were used to demonstrate that temperament profiles were more concordant for identical than for fraternal twin pairs. The results demonstrate the genetic influences on (a) the primary dimensions of temperament and (b) the developmental transformations of temperament.

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