QUANTIFICATION AND CHARACTERIZATION OF NUCLEAR GENOMES IN COMMERCIAL RED SEAWEEDS - GRACILARIALES AND GELIDIALES

Nuclear genome profiles were developed for representative species of t he Gelidiales and Gracilariales using information from present and pre vious studies of cytogenetics, cytophotometry and DNA reassociation ki netics. Results indicate that species of Gracilaria and Gracilariopsis are characterized by distinct chromosome complements of n = 24 and n = 32, respectively, a narrow range of small genome sizes (2C = 0.35-0. 45 pg) and a wide range of values for repeated and unique genome seque nces. In contrast, the Gelidiales investigated are characterized by a wide range of chromosome complements, n = 6-29, a wider range of genom e sizes (2C = 0.42-0.68 pg) and a large proportion of unique genome se quences. Nuclear genome sizes for species of the Gelidiales and Gracil ariales are compared with estimates of other red algal orders includin g the Bangiales, Ceramiales and Gigartinales.