GYMNOSPERM COMPARATIVE GENOMICS

About Gymnosperms

Gymnosperms, the first seed plants, are a taxon of considerable ecological, evolutionary, and socioeconomic importance.  Extant gymnosperms are divided into four divisions - Pinophyta (conifers), Cycadophyta (cycads), Gnetophyta (gnetophytes), and Ginkgophyta (ginkgo - see photo of ginkgo at left).  Gymnosperms first appeared as a distinct lineage more than 360 million years ago, and by the latter part of the Carboniferous period (290 MYA) they had supplanted spore-bearing vascular plants as the dominant terrestrial plant type.  The gymnosperms gave rise to the angiosperms (flowering plants), a taxon which underwent massive (and relatively rapid) adaptive radiation to supplant their gymnosperm cousins as the dominant plant group; there are roughly 250,000 extant angiosperm species while gymnosperms are represented by only 947 extant species.  However, despite their relatively low species diversity, gymnosperms as a group have still maintained a prominent position in the worlds ecosystem.  Coniferous gymnosperms still dominate the worlds temperate and boreal forest ecosystems, and in woodland and forest regions, conifers arguably are as successful as angiosperms in terms of biomass, net carbon sequestration, and general conspicuousness (Earle 2005).

Gymnosperms have played a substantial role in the history and socioeconomic development of humans.  For thousands of years, people have used wood from gymnosperms as a building material and a fuel source.  Conifer wood is still the principal home building material used by humans, and it is the main source of fibers used in paper production.  Gymnosperms are sources of pharmaceuticals and many other useful biochemicals.  Recently, there has been considerable interest in the role of gymnosperms in carbon sequestration (as a potential means of curbing rising atmospheric levels of carbon dioxide, i.e., the greenhouse effect) and their potential use as renewable biofuels.

MGEL's Gymnosperm Comparative Genomics Research

In addition to our work on pine genomics, we have initiated studies on bald cypress and ginkgo (see below).  We are working to expand our research to include many other gymnosperms as well.

About Bald Cypress

Bald cypress (Taxodium distichum L.), a representative of the conifer family Cupressaceae, is a tree of tremendous ecological importance and ornamental value.  In the southern U.S., bald cypress is the predominant tree species in the aptly named cypress swamps where it serves as a source of food and shelter for numerous and sundry organisms.  Bald cypress wood is extremely resistant to wind, water, pathogens, and pests, something that perhaps is not surprising when one considers that individual trees may spend their entire life (sometimes > 1000 years) partially submerged in water.  The highly durable wood of bald cypress is used in construction of boats, docks, bridges, and roofing shingles, although the trees relatively slow growth-rate has limited its use as a wood crop.  Unlike most conifers, bald cypress is deciduous with leaves that change from light green to brown in the fall.  Its attractive appearance and hardiness have made it a popular ornamental throughout the eastern U.S.