O DNA não é o único portador de informação genética

Como este blogger já tinha noticiado aqui: a teoria do DNA como o único portador de informação genética estava com os dias contados.

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Rethinking The Genetic Theory Of Inheritance: Heritability May Not Be Limited To DNA

ScienceDaily (Jan. 20, 2009)— Scientists at the Centre for Addiction and Mental Health (CAMH) have detected evidence that DNA may not be the only carrier of heritable information; a secondary molecular mechanism called epigenetics may also account for some inherited traits and diseases. These findings challenge the fundamental principles of genetics and inheritance, and potentially provide a new insight into the primary causes of human diseases.

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Letter Abstract

Nature Genetics

Published online: 18 January 2009 | doi:10.1038/ng.286
DNA methylation profiles in monozygotic and dizygotic twins [Requer assinatura. Se você for professor, pesquisador ou aluno em universidades pública e privadas, talve é possível acessar gratuitamente via CAPES - Periódicos

Zachary A Kaminsky1,2, Thomas Tang1, Sun-Chong Wang1,3, Carolyn Ptak1,2, Gabriel H T Oh1,2, Albert H C Wong1,2, Laura A Feldcamp1,2, Carl Virtanen4, Jonas Halfvarson5,6, Curt Tysk5,6, Allan F McRae7, Peter M Visscher7, Grant W Montgomery7, Irving I Gottesman8, Nicholas G Martin7 & Art Petronis1,2

Twin studies have provided the basis for genetic and epidemiological studies in human complex traits1, 2. As epigenetic factors can contribute to phenotypic outcomes, we conducted a DNA methylation analysis in white blood cells (WBC), buccal epithelial cells and gut biopsies of 114 monozygotic (MZ) twins as well as WBC and buccal epithelial cells of 80 dizygotic (DZ) twins using 12K CpG island microarrays3, 4. Here we provide the first annotation of epigenetic metastability of 6,000 unique genomic regions in MZ twins. An intraclass correlation (ICC)-based comparison of matched MZ and DZ twins showed significantly higher epigenetic difference in buccal cells of DZ co-twins (P = 1.2 10-294). Although such higher epigenetic discordance in DZ twins can result from DNA sequence differences, our in silico SNP analyses and animal studies favor the hypothesis that it is due to epigenomic differences in the zygotes, suggesting that molecular mechanisms of heritability may not be limited to DNA sequence differences.

1. Centre for Addiction and Mental Health, Toronto, Ontario M5T 1R8, Canada.
2. University of Toronto, Toronto, Ontario M5S 1A1, Canada.
3. Institute of Systems Biology and Bioinformatics, National Central University, Chungli 320, Taiwan.
4. University Health Network Microarray Centre, Toronto, Ontario M5G 1L7, Canada.
5. Division of Gastroenterology, Department of Medicine, 701 85 Örebro University Hospital, Örebro, Sweden.
6. School of Health and Medical Sciences, Örebro University, 701 85 Örebro, Sweden.
7. Queensland Institute of Medical Research, Brisbane 4029, Queensland, Australia.
8. University of Minnesota, Minneapolis, Minnesota 55454, USA.

Correspondence to: Art Petronis1,2 e-mail: arturas_petronis@camh.net