Evolutionary questions that address how organisms handle genetic redundancy (gene families), functionally linked genes (genes involved in a pathway) and how these genes contributed to the phenotypic diversity present in the vast array of organisms can begin to be addressed when an ideal model system is employed. The first specific aim of this proposal is to isolate and identify members of the metabolically-linked genes in the anthocyanin pathway that are involved in flower color production from members of the Hawaiian silversword alliance. The end product of the pathway is the compound anthocyanin visualized as the red, blue, and purple pigments seen in different plant tissues. The genes that will be focused on encode three enzymes in the pathway;chalcone synthase (CHS), dihydroflavonol reductase (DFR), and anthocyanin synthase (ANS). All of these genes except ANS are members of multi-gene families. The genes listed above will be cloned, sequenced, and analyzed from floral tissue in the Hawaiian silversword alliance (Asteraceae, Madiinae) a premier example of adaptative radiation, therefore it has a relatively recent evolutionary history. The second specific aim of this proposal is to isolate, identify and analyze other members of the CHS and DFR gene families from the genome of the Hawaiian silverswords and tarweeds. Examining the evolutionary history of these genes can provide insight into how metabolic pathways are built over time. Studying specific metabolic pathways in plants and how they are regulated can provide insight into other cellular pathways and this knowledge should apply across all eukaryotic taxa. Many genetic diseases that affect plants and animals are due to alterations in structural and/or regulatory genes involved in producing important end products of these pathway systems. The basic skills required for these studies are applicable to any field of molecular biology including studies of mammalian systems and human genetic disease. The knowledge gained from these types of studies are useful to researchers in the field of genomics and pharmaceutical drug design. The study proposed above is a pilot study to begin to look at the bigger picture of gene redundancy, key morphological loci, and evolutionary linkage between structural and regulatory genes. These results will provide insight into comparing the evolutionary history of functionally linked genes in an important pathway and provide more information for ongoing conservation efforts in Hawaiian Silversword.
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