The search for circadian clock components in humans: new perspectives for association studies
Individual circadian clocks entrain differently to environmental cycles (zeitgebers, e.g., light and darkness), earlier or later within the day, leading to different chronotypes. In human populations, the distribution of chronotypes forms a bell-shaped curve, with the extreme early and late types _...
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2008-08-01
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doaj-9e2b7c87c4fe45f29c5ac670ef8012e62020-11-24T23:12:47ZengAssociação Brasileira de Divulgação CientíficaBrazilian Journal of Medical and Biological Research0100-879X1414-431X2008-08-01418716721The search for circadian clock components in humans: new perspectives for association studiesK.V. AllebrandtT. RoennebergIndividual circadian clocks entrain differently to environmental cycles (zeitgebers, e.g., light and darkness), earlier or later within the day, leading to different chronotypes. In human populations, the distribution of chronotypes forms a bell-shaped curve, with the extreme early and late types _ larks and owls, respectively _ at its ends. Human chronotype, which can be assessed by the timing of an individual's sleep-wake cycle, is partly influenced by genetic factors - known from animal experimentation. Here, we review population genetic studies which have used a questionnaire probing individual daily timing preference for associations with polymorphisms in clock genes. We discuss their inherent limitations and suggest an alternative approach combining a short questionnaire (Munich ChronoType Questionnaire, MCTQ), which assesses chronotype in a quantitative manner, with a genome-wide analysis (GWA). The advantages of these methods in comparison to assessing time-of-day preferences and single nucleotide polymorphism genotyping are discussed. In the future, global studies of chronotype using the MCTQ and GWA may also contribute to understanding the influence of seasons, latitude (e.g., different photoperiods), and climate on allele frequencies and chronotype distribution in different populations.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2008000800013Human clock genesChronotypeMorningnessAssociation studiesLatitudinal hypothesis |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
K.V. Allebrandt T. Roenneberg |
spellingShingle |
K.V. Allebrandt T. Roenneberg The search for circadian clock components in humans: new perspectives for association studies Brazilian Journal of Medical and Biological Research Human clock genes Chronotype Morningness Association studies Latitudinal hypothesis |
author_facet |
K.V. Allebrandt T. Roenneberg |
author_sort |
K.V. Allebrandt |
title |
The search for circadian clock components in humans: new perspectives for association studies |
title_short |
The search for circadian clock components in humans: new perspectives for association studies |
title_full |
The search for circadian clock components in humans: new perspectives for association studies |
title_fullStr |
The search for circadian clock components in humans: new perspectives for association studies |
title_full_unstemmed |
The search for circadian clock components in humans: new perspectives for association studies |
title_sort |
search for circadian clock components in humans: new perspectives for association studies |
publisher |
Associação Brasileira de Divulgação Científica |
series |
Brazilian Journal of Medical and Biological Research |
issn |
0100-879X 1414-431X |
publishDate |
2008-08-01 |
description |
Individual circadian clocks entrain differently to environmental cycles (zeitgebers, e.g., light and darkness), earlier or later within the day, leading to different chronotypes. In human populations, the distribution of chronotypes forms a bell-shaped curve, with the extreme early and late types _ larks and owls, respectively _ at its ends. Human chronotype, which can be assessed by the timing of an individual's sleep-wake cycle, is partly influenced by genetic factors - known from animal experimentation. Here, we review population genetic studies which have used a questionnaire probing individual daily timing preference for associations with polymorphisms in clock genes. We discuss their inherent limitations and suggest an alternative approach combining a short questionnaire (Munich ChronoType Questionnaire, MCTQ), which assesses chronotype in a quantitative manner, with a genome-wide analysis (GWA). The advantages of these methods in comparison to assessing time-of-day preferences and single nucleotide polymorphism genotyping are discussed. In the future, global studies of chronotype using the MCTQ and GWA may also contribute to understanding the influence of seasons, latitude (e.g., different photoperiods), and climate on allele frequencies and chronotype distribution in different populations. |
topic |
Human clock genes Chronotype Morningness Association studies Latitudinal hypothesis |
url |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2008000800013 |
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