Resumen

PONCE-MARQUEZ, Ma. Edith et al. Cytogenetic study in Mexican populations of Gelidium sclerophyllum (Gelidiales, Rhodophyta). Hidrobiológica [online]. 2009, vol.19, n.2, pp.85-93. ISSN 0188-8897.

The aim of this study was to establish the presence of tetrasporophytes and gametophytes in populations of Gelidium sclerophyllum, a species endemic to the Eastern Tropical Pacific. The results are based on karyological and chromosome analysis of six populations from the Las Cuatas beach, Guerrero, Mexico, during a seasonal cycle. It were confirmed the presence of tetrasporophytic and gametophytic thalli in populations, proving that the Polysiphonia type of the alternation of generations cycle was present at least one period within the annual cycle. The results establish a variation of the chromosome number of 3, 4 and 5 chromosomes in the tetrasporophyte whose modal number was 2n = 4 chromosomes, and a variation of 1, 2 and 3 chromosomes in the gametophyte (modal number n = 2). Chromosome values were found in the same thallus, but with variations in their frequency of occurrence in different populations throughout the year.

Palabras llave : Chromosomes; cytogenetics; karyotype; Rhodophyta; Gelidium.

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