Cytogenetics of Diphysa americana (Mill.) M.Sousa (Leguminosae-Papilionoideae-dalbergioid clade), a rare species from the coast of Oaxaca, Mexico
Por:
Tapia-Pastrana F.
Publicada:
1 ene 2023
Resumen:
Diphysa Jacq. is an essentially Mexican and Central American genus that includes 21 species and only one cytogenetic report. In this work, a surface spread and air-drying method was used to obtain the karyotype of Diphysa americana (Mill) M.Sousa, a rare native tree that grows in a coastal town in the State of Oaxaca, Mexico. Metaphase cells showed a 2n = 20, consistent with the predominant diploid number in the dalbergioid clade. This number contrasts with a previously reported 2n = 16. The karyotypic formula 5m + 5sm, first proposed for a species of the genus, denotes a slightly asymmetric karyotype. The presence of secondary constrictions associated with satellites on the short arms of a pair of sm chromosomes and other cytogenetic parameters require studies in other species of the genus to verify their taxonomic util-ity. In addition, cells in prometaphase exhibited a circular fragment of unknown origin like that observed in a species of the genus Aeschynomene, also dalbergioid. This fragment could be related to extrachromosomal circular DNA (eccDNA) observed in other plants. Diphysa is a small, cytogenetically favorable genus, and further studies will exhibit the karyotypic diversity that underlies its diversification. © 2023 Fernando Tapia-Pas-trana.
Filiaciones:
Tapia-Pastrana F.:
Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México, Laboratorio de Genecología, Batalla 5 de mayo s/n esquina Fuerte de Loreto, Col. Ejército de Oriente, Iztapalapa, Ciudad de México, C.P. 09230, Mexico
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