Systematics Section / ASPT
Tate, Jennifer A. , Chen, Z. Jeffrey , Soltis, Pamela S. , Soltis, Douglas E. .
Gene expression in Tragopogon miscellus (Asteraceae),
a recent and reciprocally formed allopolyploid.
Despite recent advances in our understanding of polyploid evolution, little is known about patterns of gene expression in naturally occurring allopolyploid populations relative to their diploid parents. Likewise, although most polyploid species have formed recurrently, it is unclear whether populations of independent origin exhibit similar or divergent patterns of gene expression. To address these issues, we are exploring patterns of gene expression in Tragopogon miscellus, an allotetraploid of recent (less than 80 years) and recurrent origin, and its diploid progenitors, T. dubius and T. pratensis, using cDNA-amplified fragment length polymorphisms (cDNA-AFLP) and independent RT-PCR. Multiple individuals from both the diploid and tetraploid populations are being included in the study to assess intra- and interpopulational differences, although previous genetic work on these species demonstrated that very little intrapopulational variation exists. Our data reveal that both gene silencing and activation of novel transcripts have occurred in the allotetraploids. Gene silencing corresponding to maternal and paternal expression patterns was detected in the reciprocally formed allotetraploids. The differentially expressed genes showed high sequence similarity to genes of known function and appear to be involved in a wide array of cellular processes, such as carbohydrate metabolism, signal transduction, protein transport and degradation, and cell division. Individuals within and between the reciprocally formed populations may express the same parental gene copy (homoeolog) or different copies. Differential expression of homoeologous genes in these reciprocally formed allopolyploid populations reinforces the potential evolutionary importance of multiple origins.
1 - Texas A&M University, Soil and Crop Sciences, Mail Stop 2474, College Station, Texas, 77840-2474
2 - University of Florida, Department of Natural History, Florida Museum of Natural History, P.O. Box 117800, Gainesville, Florida, 32611-7800, USA
3 - University of Florida, Department of Botany, 220 Bartram Hall, P.O. Box 118526, Gainesville, Florida, 32611-8526, USA
Presentation Type: Paper
Location: Cottonwood B (Snowbird Center)
Date: Monday, August 2nd, 2004
Time: 11:45 AM