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Type I MADS-Box Genes Have Experienced Faster Birth-and-Death Evolution Than Type II MADS-Box Genes in Angiosperms
Jongmin Nam, Joonyul Kim, Shinyoung Lee, Gynheung An, Hong Ma and Masatoshi Nei
Proceedings of the National Academy of Sciences of the United States of America
Vol. 101, No. 7 (Feb. 17, 2004), pp. 1910-1915
Published by: National Academy of Sciences
Stable URL: http://www.jstor.org/stable/3371369
Page Count: 6
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Plant MADS-box genes form a large gene family for transcription factors and are involved in various aspects of developmental processes, including flower development. They are known to be subject to birth-and-death evolution, but the detailed features of this mode of evolution remain unclear. To have a deeper insight into the evolutionary pattern of this gene family, we enumerated all available functional and nonfunctional (pseudogene) MADS-box genes from the Arabidopsis and rice genomes. Plant MADS-box genes can be classified into types I and II genes on the basis of phylogenetic analysis. Conducting extensive homology search and phylogenetic analysis, we found 64 presumed functional and 37 nonfunctional type I genes and 43 presumed functional and 4 nonfunctional type II genes in Arabidopsis. We also found 24 presumed functional and 6 nonfunctional type I genes and 47 presumed functional and 1 nonfunctional type II genes in rice. Our phylogenetic analysis indicated there were at least about four to eight type I genes and ≈ 15-20 type II genes in the most recent common ancestor of Arabidopsis and rice. It has also been suggested that type I genes have experienced a higher rate of birth-and-death evolution than type II genes in angiosperms. Furthermore, the higher rate of birth-and-death evolution in type I genes appeared partly due to a higher frequency of segmental gene duplication and weaker purifying selection in type I than in type II genes.
Proceedings of the National Academy of Sciences of the United States of America © 2004 National Academy of Sciences