Nuclear DNA C-values in 30 species double the familial representation in pteridophytes.
Nuclear DNA C-values and genome size are important biodiversity characters with fundamental biological significance. Yet C-value data for pteridophytes, a diverse group of vascular plants with approx. 9000 extant species, remain scarce. A recent survey by Bennett and Leitch (2001, Annals of Botany 87: 335-345) found that C-values were reported for only 48 pteridophyte species. To improve phylogenetic representation in this group and to check previously reported estimates, C-values for 30 taxa in 17 families were measured using flow cytometry for all but one species. This technique proved generally applicable, but the ease with which C-value data were generated varied greatly between materials. Comparing the new data with those previously published revealed several large discrepancies. After discounting doubtful data, C-values for 62 pteridophyte species remained acceptable for analysis. The present work has increased the number of such species' C-values by 93 %, and more than doubled the number of families represented (from 10 to 21). Analysis shows that pteridophyte C-values vary approx. 450-fold, from 0-16 pg in Selaginella kraussiana to 72.7 pg in Psilotum nudum var. gasa. Superimposing C-value data onto a robust phylogeny of pteridophytes suggests some possible trends in C-value evolution and highlights areas for future work.
Jodrell Laboratory, Royal Botanic Gardens, Richmond, Surrey, UK.
Renate
R
Obermayer
Ilia J
IJ
Leitch
Lynda
L
Hanson
Michael D
MD
Bennett
D002467:Cell Nucleus / Q000235:genetics*; D002875:Chromosomes / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics* / Q000302:isolation & purification; D003625:Data Collection; D029624:Ferns / Q000145:classification / Q000235:genetics* / Q000502:physiology; D005434:Flow Cytometry; D018745:Genome, Plant; D010802:Phylogeny; D011003:Ploidies; D013045:Species Specificity; D013170:Spores
D018744:DNA, Plant