Cytogenetics and Evolutionary Analysis of Lophanthera, an Amazonian Arboreal Malpighiaceae.

Abstract

Only 2 chromosome counts are reported for Lophanthera, an Amazonian arboreal genus with 5 species that belongs to sub-family Byrsonimoideae. Cytological studies were carried out in Lophanthera lactescens Ducke to verify the haploid and diploid chromosome numbers (n=6, 2n=12) of a previously unstudied population. The meiotic process was regular and no abnormalities were found. The first chromosomal ideogram for the genus was constructed and shows a predominance of metacentric pairs (5m+1sm). In order to explain the increased lengths of its chromosomes (5.3μm to 11.8μm) and the primitive position of the genus in Malpighiaceae, in situ hybridization with a telomeric probe was performed. We observed the distribution of the telomeric sequences. No interstitial sequences were found. In addition to the symmetric karyotype observed, this assay indicates that probably no fusion or translocations of segments has occurred along the karyotype evolution of Lophanthera.