Karyotypes and fluorescent chromosome banding in South African Lycium (Solanaceae)

STIEFKENS L.,; LAS PEÑAS M. L.; BERNARDELLO G.; LEVIN R. A.; MILLER J.

CARYOLOGIA

UNIV FLORENCE BOTANY INST

Año: 2010 vol. 63 p. 50 - 61

0008-7114

Analysis of chromosomes of several South African Lycium resulted diploid (2n=24: L. amoenum, L. bosciifolium, L. ferocissimum, L. oxycarpum, L. tenue), tetraploid (2n=48: L. tetrandrum, L. strandveldense, L. hantamense), or hexaploid (2n=72: L. gariepense) counts. Chromosomes in all species were small (mean length = 2.00 m; mean haploid genome length = 23.77 m). All species shared a highly symmetrical karyotype formula with 10 m pairs and 2 sm pairs, except L. bosciifolium with only one sm pair. The first m pair had a terminal microsatellite on the short arms. Fluorescent chromosome banding patterns with CMA/DAPI staining in the diploids showed NOR-associated heterochromatin in the first satellited pair. The tetraploids L. tetrandrum and L. hantamense had two chromosome pairs with a CMA+/DAPI- terminal band. Phylogenetic studies have shown that the southern African species are included in a monophyletic group including all Old World Lycium; these species are likely of recent origin and, despite ploidy differences, karyotypes are remarkably similar among species. Data available for South American, Asian, and southern African Lycium indicate that there is a common pattern of mostly m chromosomes in which a few cryptic chromosomal rearrangements may have occurred, suggesting that karyotypic orthoselection has preserved similar patterns among species. Thus, these data suggest that morphological diversification of Lycium was not accompanied by changes in chromosome morphology.