Karyology and nuclear DNA quantification of four species ofChaetomorpha (Cladophorales, Chlorophyta) from the western Atlantic

Abstract

Chromosome numbers are given for four species of Chaetomorpha from the warm temperate and tropical western Atlantic. The basic chromosome number is six, with three median and three submedian chromosomes. Chaetomorpha species represent a polyploid series, with numbers of 12, 18 and 24 found in the present study. Microspectrophotometry data for each spedes were quantified by reference to standards with known DNA contents. Results indicate similar 2X =IC = 12 genome sizes for C. aerea {0.20 pg) and C. brachygona (0.26 pg}, and for C. antennina (0.53 pg) and C. melagonium (0.58 pg). These findings are compared with karyological features of Cladophora species to characterize the karyology of the cladophoralean genome.

Microsatellite markers in an invasive strain of Asparagopsis taxiformis (Bonnemaisoniales, Rhodophyta): Insights in ploidy level and sexual reproduction

“…Endo-polyploidy (i.e. the multiplication of DNA and chromosomal number without cell division) was already proposed for Phaeophytes (Garbary and Clarke, 2002), Chlorophytes (Hinson and Kapraun, 1991) and Rhodophytes (Goff and Coleman, 1990). Variations in DNA content can occur via endo-reduplication or during mitosis Coleman, 1986, 1990).…”

Mediterranean Species of Caulerpa Are Polyploid with Smaller Genomes in the Invasive Ones

“…larger flowers or leaves) to ensure growth by cell enlargement in situations that prevent growth by cell division [72], [73]. Endopolyploidy was already reported in algae for Phaeophyceae [74], [75], [76], Chlorophyta [21], [77] and Rhodophyta [66], [78]. Since endopolyploidy, by multiplying the number of gene copies contributes to the mass of a growing tissue, this could be one of the strategies in Caulerpa for efficient clonal growth, compensating a small role of sexual reproduction in space colonization.…”

Life History and Cytology of the Freshwater Alga Chaetomorpha exilissima sp. nov (Cladophorales, Chlorophyta).

“…exilissima different than in the rest of the studied species. According with Wik-SjOstedt (1970) and Kapraun and Gargiulo (1987a) this proportion is in Cladophora 1: 1, being also the case of Chaetomorpha (Hinson and Kapraun 1991) since the basic dotation of six chromosomes includes three sm and three m chromosomes. Consequently, Ch.…”

“…exilissima is n =18 showing median (m) and submedian (sm) centromeres in a proportion, sm : m = 1 : 2, (Fig. 13) as normal in many species of Cladophora (Sinha 1963, Wik-SjOstedt 1970, Kapraun and Gargiulo 1987a, b, Parodi and Caceres 1995, Rhizoclonium (Parodi and Caceres 1992) and Chaetomorpha (Hinson andKapraun 1991, Kapraun 1993). Chromosome size extend from 0.7-1.…”