A first generation cytogenetic ideogram for the Florida manatee (Trichechus manatus latirostris) based on multiple chromosome banding techniques

Abstract

Detailed chromosome studies were conducted for the Florida manatee (Trichechus manatus latirostris) utilizing primary chromosome banding techniques (G-and Q-banding). Digital microscopic imaging methods were employed and a standard G-banded karyotype was constructed for both sexes. Based on chromosome banding patterns and measurements obtained in these studies, a standard karyotype and ideogram are proposed. Characterization of additional cytogenetic features of this species by supplemental chromosome banding techniques, C-banding (constitutive heterochromatin), Ag-NOR staining (nucleolar organizer regions), and DA/DAPI staining, was also performed. These studies provide detailed cytogenetic data for T. manatus latirostris, which could enhance future genetic mapping projects and interspecific and intraspecific genomic comparisons by techniques such as zoo-FISH.

Chromosome painting among Proboscidea, Hyracoidea and Sirenia: support for Paenungulata (Afrotheria, Mammalia) but not Tethytheria

“…The numbering and organization of the respective G-banded karyotypes followed previous studies (elephant, Houck et al 2001; manatee, Gray et al 2002; aardvark, Yang et al 2003 a ), the exception being P. capensis . Following a comparison between the hyrax karyotype presented here and that recently published by Froenicke (2006), intrachromosomal differences were found between several chromosomes (table S1 in electronic supplementary material), making some of the homology comparisons problematic.…”

“…These include the Florida manatee, 2 n =48 (Gray et al 2002), the Amazonian manatee, Trichechus inunguis , 2 n =56 (Assis et al 1988) and the dugong, Dugong dugon , 2 n =50 (Short 1984). Both G- and C-banding data for the Amazonian manatee are available for comparison with the Florida manatee.…”

Chromosome painting in the manatee supports Afrotheria and Paenungulata

“…Routine procedures were used for chromosome preparations. We followed the chromosome nomenclature as previously published [12] pairing and grouping chromosomes by banding patterns, relative lengths and morphology.…”

“…Following solid staining, chromosome-banding procedures allowed for the identification of individual chromosome regions. Giemsa and trypsin staining, or GTG-banding, was used to create karyotypes and ideograms for the Florida manatee [12] and the Amazonian manatee [13]. …”

The Chromosomes of Afrotheria and Their Bearing on Mammalian Genome Evolution

“…The banded chromosomes have already been described for 2 of the 4 known living Sirenia: the Amazonian manatee Trichechus inunguis (2n = 56) and the Florida manatee T . manatus latirostris (2n = 48) [Assis et al, 1988;Gray et al, 2002]. GTG-banded karyotypes of 2 Proboscidea, the African and Asian elephants ( Loxodonta africana and Elephas maximus , respectively) were also described and compared, allowing the detection of a high homology between both karyotypes [Houck et al, 2001].…”