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Acc homoeoloci and the evolution of wheat genomes.
Proc Natl Acad Sci U S A. 2008 Jul 15; 105(28):9691-6.PN

Abstract

The DNA sequences of wheat Acc-1 and Acc-2 loci, encoding the plastid and cytosolic forms of the enzyme acetyl-CoA carboxylase, were analyzed with a view to understanding the evolution of these genes and the origin of the three genomes in modern hexaploid wheat. Acc-1 and Acc-2 loci from each of the wheats Triticum urartu (A genome), Aegilops tauschii (D genome), Triticum turgidum (AB genome), and Triticum aestivum (ABD genome), as well as two Acc-2-related pseudogenes from T. urartu were sequenced. The 2.3-2.4 Mya divergence time calculated here for the three homoeologous chromosomes, on the basis of coding and intron sequences of the Acc-1 genes, is at the low end of other estimates. Our clock was calibrated by using 60 Mya for the divergence between wheat and maize. On the same time scale, wheat and barley diverged 11.6 Mya, based on sequences of Acc and other genes. The regions flanking the Acc genes are not conserved among the A, B, and D genomes. They are conserved when comparing homoeologous genomes of diploid, tetraploid, and hexaploid wheats. Substitution rates in intergenic regions consisting primarily of repetitive sequences vary substantially along the loci and on average are 3.5-fold higher than the Acc intron substitution rates. The composition of the Acc homoeoloci suggests haplotype divergence exceeding in some cases 0.5 Mya. Such variation might result in a significant overestimate of the time since tetraploid wheat formation, which occurred no more than 0.5 Mya.

Authors+Show Affiliations

Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

18599450

Citation

Chalupska, D, et al. "Acc Homoeoloci and the Evolution of Wheat Genomes." Proceedings of the National Academy of Sciences of the United States of America, vol. 105, no. 28, 2008, pp. 9691-6.
Chalupska D, Lee HY, Faris JD, et al. Acc homoeoloci and the evolution of wheat genomes. Proc Natl Acad Sci USA. 2008;105(28):9691-6.
Chalupska, D., Lee, H. Y., Faris, J. D., Evrard, A., Chalhoub, B., Haselkorn, R., & Gornicki, P. (2008). Acc homoeoloci and the evolution of wheat genomes. Proceedings of the National Academy of Sciences of the United States of America, 105(28), 9691-6. https://doi.org/10.1073/pnas.0803981105
Chalupska D, et al. Acc Homoeoloci and the Evolution of Wheat Genomes. Proc Natl Acad Sci USA. 2008 Jul 15;105(28):9691-6. PubMed PMID: 18599450.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Acc homoeoloci and the evolution of wheat genomes. AU - Chalupska,D, AU - Lee,H Y, AU - Faris,J D, AU - Evrard,A, AU - Chalhoub,B, AU - Haselkorn,R, AU - Gornicki,P, Y1 - 2008/07/03/ PY - 2008/7/5/pubmed PY - 2008/9/4/medline PY - 2008/7/5/entrez SP - 9691 EP - 6 JF - Proceedings of the National Academy of Sciences of the United States of America JO - Proc. Natl. Acad. Sci. U.S.A. VL - 105 IS - 28 N2 - The DNA sequences of wheat Acc-1 and Acc-2 loci, encoding the plastid and cytosolic forms of the enzyme acetyl-CoA carboxylase, were analyzed with a view to understanding the evolution of these genes and the origin of the three genomes in modern hexaploid wheat. Acc-1 and Acc-2 loci from each of the wheats Triticum urartu (A genome), Aegilops tauschii (D genome), Triticum turgidum (AB genome), and Triticum aestivum (ABD genome), as well as two Acc-2-related pseudogenes from T. urartu were sequenced. The 2.3-2.4 Mya divergence time calculated here for the three homoeologous chromosomes, on the basis of coding and intron sequences of the Acc-1 genes, is at the low end of other estimates. Our clock was calibrated by using 60 Mya for the divergence between wheat and maize. On the same time scale, wheat and barley diverged 11.6 Mya, based on sequences of Acc and other genes. The regions flanking the Acc genes are not conserved among the A, B, and D genomes. They are conserved when comparing homoeologous genomes of diploid, tetraploid, and hexaploid wheats. Substitution rates in intergenic regions consisting primarily of repetitive sequences vary substantially along the loci and on average are 3.5-fold higher than the Acc intron substitution rates. The composition of the Acc homoeoloci suggests haplotype divergence exceeding in some cases 0.5 Mya. Such variation might result in a significant overestimate of the time since tetraploid wheat formation, which occurred no more than 0.5 Mya. SN - 1091-6490 UR - https://www.unboundmedicine.com/medline/citation/18599450/Acc_homoeoloci_and_the_evolution_of_wheat_genomes_ L2 - http://www.pnas.org/cgi/pmidlookup?view=long&pmid=18599450 DB - PRIME DP - Unbound Medicine ER -