Nuclear DNA content estimations and nuclear development patterns in Antarctic macroalgae

Abstract

Nuclear DNA content of marine macroalgae is known for only about a 3% of the globally known taxa, and so far, the only available data concerning marine Antarctic macroalgae refer to the Phaeophyceae Ascoseira mirabilis and Desmarestia antarctica. As these data can be useful for species delimitation when combined with other taxonomical information, we aimed to expand the available number of measurements in the understudied Antarctic seaweed flora. To address this, we measured the nuclear DNA content of 12 Antarctic marine algae (seven Rhodophyceae and five Phaeophyceae). Nuclear DNA analyses were carried out by spectrofluorimetry and image analysis from samples conserved in Carnoy, using DAPI as DNA marker. For ten of these taxa, our values represent the first estimations to date. The nuclear DNA content estimates obtained for the Antarctic red algae examined vary between 2C = 0.38 pg in Gigartina skottsbergii and 2C = 1.63 pg in Neuroglossum delesseriae. In brown algae, the values range from 2C = 0.18 pg in both Desmarestia antarctica and Desmarestia menziesii to 2C = 0.96 pg in Phaeurus antarcticus. Furthermore, this study allowed us to identify nuclear developmental patterns for the first time in two Antarctic seaweeds (Ballia callitricha and Neuroglossum delesseriae).