Cytotypes and Meiotic Behavior in Mexican Populations of Three Species of Echeandia (Liliaceae)

Abstract

Analysis of 8 populations of 3 species of Echeandia echeandioides, E. tenuis and E. mexicana showed that all were diploid, chromosome counts were 2n=16, n=8 (x=8). Each species had a different karyotype. The three species also presented different cytotypes in all populations. However, the presence of the same cytotype in each population suggested that all populations originated from a single clone by vegetative reproduction. Cytotype variation was observed in heteromorphic pairs of metacentric, submetacentric, subtelocentric and chromosomes with satellite. The meiotic analysis had heterozygotic exchanges. MI analysis showed heteromorphic IIs and IVs. Al analysis displayed U-type chromatid exchange (3.91%-0.30%) and sub-chromatid aberrations (12.78%-1.91%). Lagging chromosomes were recorded in AI in 4 populations of E. echeandioides and E. tenuis. Ea mexicana did not present this type of aberration. Based on these results, we can suggest that exchanges had played an important role in the evolution of the genus.