You are not currently logged in.
Access JSTOR through your library or other institution:
If You Use a Screen ReaderThis content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
De Novo Insertion of an Intron into the Mammalian Sex Determining Gene, SRY
Rachel J. Waugh O'Neill, Francine E. Brennan, Margaret L. Delbridge, Ross H. Crozier and Jennifer A. Marshall Graves
Proceedings of the National Academy of Sciences of the United States of America
Vol. 95, No. 4 (Feb. 17, 1998), pp. 1653-1657
Published by: National Academy of Sciences
Stable URL: http://www.jstor.org/stable/44339
Page Count: 5
You can always find the topics here!Topics: Introns, Genomics, Marsupials, DNA, Polymerase chain reaction, Generally accepted auditing standards, Evolution, Reverse transcriptase polymerase chain reaction, sry genes, Clean Air Act
Were these topics helpful?See something inaccurate? Let us know!
Select the topics that are inaccurate.
Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.
Preview not available
Two theories have been proposed to explain the evolution of introns within eukaryotic genes. The introns early theory, or ``exon theory of genes,'' proposes that introns are ancient and that recombination within introns provided new exon structure, and thus new genes. The introns late theory, or ``insertional theory of introns,'' proposes that ancient genes existed as uninterrupted exons and that introns have been introduced during the course of evolution. There is still controversy as to how intron-exon structure evolved and whether the majority of introns are ancient or novel. Although there is extensive evidence in support of the introns early theory, phylogenetic comparisons of several genes indicate recent gain and loss of introns within these genes. However, no example has been shown of a protein coding gene, intronless in its ancestral form, which has acquired an intron in a derived form. The mammalian sex determining gene, SRY, is intronless in all mammals studied to date, as is the gene from which it recently evolved. However, we report here comparisons of genomic and cDNA sequences that now provide evidence of a de novo insertion of an intron into the SRY gene of dasyurid marsupials. This recently (approximately 45 million years ago) inserted sequence is not homologous with known transposable elements. Our data demonstrate that introns may be inserted as spliced units within a developmentally crucial gene without disrupting its function.
Proceedings of the National Academy of Sciences of the United States of America © 1998 National Academy of Sciences