Chromosomal traits of Chamaelirium luteum (Melanthiaceae) with particular focus on the large heterochromatic centromeres

Chromosomal traits of Chamaelirium luteum (Melanthiaceae) with particular focus on the large heterochromatic centromeres

Chromosomal morphology and behavior during the mitotic cell cycle and properties as to the DNA base composition in heterochromatin of Chamaelirium luteum from eastern North America were investigated by conventional and fluorescent banding methods. The chromosomes proved to have no primary constrictions; instead, they had unusually large heterochromatic monocentromeres termed“macrocentromeres”that were as thick as the chromosome arms and tended to protrude poleward at metaphase. It also became evident that the centromeres are rich in AT base pairs, whereas the satellites are GC-rich. Data suggested that the centromeric domains were tightly compacted almost through the cell cycle and situated at the nuclear periphery during telophase, interphase and prophase. The roles of centromeres and their causality to the property of centromeric DNA were discussed briefly. Some chromosomal traits of C. luteum were compared with those known for Asian congeners reported to have holocentromeres.