Group Title: BMC Evolutionary Biology
Title: Chromosome painting in the manatee supports Afrotheria and Paenungulata
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Title: Chromosome painting in the manatee supports Afrotheria and Paenungulata
Series Title: BMC Evolutionary Biology
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Language: English
Creator: Kellogg, Margaret
Burkett, Sandra
Dennis, Thomas
Stone, Gary
Gray, Brian
McGuire, Peter
Zori, Roberto
Stanyon, Roscoe
Publication Date: 2007
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Abstract: BACKGROUND:Sirenia (manatees, dugongs and Stellar's sea cow) have no evolutionary relationship with other marine mammals, despite similarities in adaptations and body shape. Recent phylogenomic results place Sirenia in Afrotheria and with elephants and rock hyraxes in Paenungulata. Sirenia and Hyracoidea are the two afrotherian orders as yet unstudied by comparative molecular cytogenetics. Here we report on the chromosome painting of the Florida manatee.RESULTS:The human autosomal and X chromosome paints delimited a total of 44 homologous segments in the manatee genome. The synteny of nine of the 22 human autosomal chromosomes (4, 5, 6, 9, 11, 14, 17, 18 and 20) and the X chromosome were found intact in the manatee. The syntenies of other human chromosomes were disrupted in the manatee genome into two to five segments. The hybridization pattern revealed that 20 (15 unique) associations of human chromosome segments are found in the manatee genome: 1/15, 1/19, 2/3 (twice), 3/7 (twice), 3/13, 3/21, 5/21, 7/16, 8/22, 10/12 (twice), 11/20, 12/22 (three times), 14/15, 16/19 and 18/19.CONCLUSION:There are five derived chromosome traits that strongly link elephants with manatees in Tethytheria and give implicit support to Paenungulata: the associations 2/3, 3/13, 8/22, 18/19 and the loss of the ancestral eutherian 4/8 association. It would be useful to test these conclusions with chromosome painting in hyraxes. The manatee chromosome painting data confirm that the associations 1/19 and 5/21 phylogenetically link afrotherian species and show that Afrotheria is a natural clade. The association 10/12/22 is also ubiquitous in Afrotheria (clade I), present in Laurasiatheria (clade IV), only partially present in Xenarthra (10/12, clade II) and absent in Euarchontoglires (clade III). If Afrotheria is basal to eutherians, this association could be part of the ancestral eutherian karyotype. If afrotherians are not at the root of the eutherian tree, then the 10/12/22 association could be one of a suite of derived associations linking afrotherian taxa.
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Research article

Chromosome painting in the manatee supports Afrotheria and
Paenungulata
Margaret E Kellogg', Sandra Burkett2, Thomas R Dennis3, Gary Stone2,
Brian A Gray3, Peter M McGuire4, Roberto T Zori3 and Roscoe Stanyon*5


Address: 'College of Veterinary Medicine, University of Florida, PO BOX 100245, Gainesville, FL 32610-0245, USA, 2Comparative Molecular
Cytogenetics Core, National Cancer Institute, Frederick, MD 21702, USA, 3Department of Pediatrics, Division of Genetics, University of Florida,
PO Box 100296, UFHSC, Gainesville, FL 32610, USA, 4Department of Biochemistry and Molecular Biology, University of Florida, PO Box 100245,
College of Medicine, Gainesville, FL 32610, USA and 5Department of Animal Biology and Genetics, University of Florence, Florence, Italy, Via del
Proconsolo 12, 50122 Florence, Italy (formerly at NCI, Frederick)
Email: Margaret E Kellogg kelloggm@gmail.com; Sandra Burkett sburkett@ncifcrf.gov; Thomas R Dennis tdennis@tgen.org;
Gary Stone gstone@ncifcrf.gov; Brian A Gray grayb@pathology.ufl.edu; Peter M McGuire pmcguire@biochem.med.ufl.edu;
Roberto T Zori zorirt@peds.ufl.edu; Roscoe Stanyon* roscoe.stanyon@unifi.it
* Corresponding author



Published: 23 January 2007 Received: 18 October 2006
BMC Evolutionary Biology 2007, 7:6 doi: 10.1 186/1471-2148-7-6 Accepted: 23 January 2007
This article is available from: http://www.biomedcentral.com/1471-2148/7/6
2007 Kellogg et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.



Abstract
Background: Sirenia (manatees, dugongs and Stellar's sea cow) have no evolutionary relationship
with other marine mammals, despite similarities in adaptations and body shape. Recent
phylogenomic results place Sirenia in Afrotheria and with elephants and rock hyraxes in
Paenungulata. Sirenia and Hyracoidea are the two afrotherian orders as yet unstudied by
comparative molecular cytogenetics. Here we report on the chromosome painting of the Florida
manatee.
Results: The human autosomal and X chromosome paints delimited a total of 44 homologous
segments in the manatee genome. The synteny of nine of the 22 human autosomal chromosomes
(4, 5, 6, 9, I I, 14, 17, 18 and 20) and the X chromosome were found intact in the manatee. The
syntenies of other human chromosomes were disrupted in the manatee genome into two to five
segments. The hybridization pattern revealed that 20 (15 unique) associations of human
chromosome segments are found in the manatee genome: 1/15, 1/19, 2/3 (twice), 3/7 (twice), 3/13,
3/21, 5/21, 7/16, 8/22, 10/12 (twice), 1 1/20, 12/22 (three times), 14/15, 16/19 and 18/19.
Conclusion: There are five derived chromosome traits that strongly link elephants with manatees
in Tethytheria and give implicit support to Paenungulata: the associations 2/3, 3/13, 8/22, 18/19 and
the loss of the ancestral eutherian 4/8 association. It would be useful to test these conclusions with
chromosome painting in hyraxes. The manatee chromosome painting data confirm that the
associations 1/19 and 5/21 phylogenetically link afrotherian species and show that Afrotheria is a
natural clade. The association 10/12/22 is also ubiquitous in Afrotheria (clade I), present in
Laurasiatheria (clade IV), only partially present in Xenarthra (10/12, clade II) and absent in
Euarchontoglires (clade III). If Afrotheria is basal to eutherians, this association could be part of the
ancestral eutherian karyotype. If afrotherians are not at the root of the eutherian tree, then the 10/
12/22 association could be one of a suite of derived associations linking afrotherian taxa.




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Background
Recently the molecular based approaches of super-ordinal
grouping of extant eutherians (Afrotheria, Euarchontog-
lires, Laurasiatheria and Xenarthra) has gained popularity
[1-3]. However, one of the four proposed super-orders,
Afrotheria, is controversial because it unites morphologi-
cally distinct species of African placentals (golden moles,
tenrecs, otter shrews, elephant shrews, aardvarks, hyraxes,
elephants and sirenians). Within Afrotheria, sirenians,
elephants and hyraxes form a clade called Paenungulata.
There is little morphological or paleontological evidence
that provides support for Afrotheria [4]. A movable snout
was hypothesized as a synapomorphic trait, but this fea-
ture is apparently not homologous across different afroth-
erian lineages[5]. More recently, it was proposed that
aspects of placentation could provide a synapomorphy for
this assemblage [6,7]. Some outstanding issues in higher
eutherian phylogenomics include the exact root of the
placental tree, the relationships within the super-ordinal
clade Laurasiatheria (moles, hedgehogs, shrews, bats,
cetaceans, ungulates, pangolins and carnivores), and
resolving the trichotomy of sirenians, elephants and
hyraxes [8].

Sirenia and Hyracoidea are the two afrotherian orders
remaining to be investigated with molecular cytogenetic
techniques. In this paper, the chromosome painting of the
Florida manatee (Trichechus manatus latirostris) is
reported. These data should be a valuable addition to our
understanding of afrotherian relationships and the euthe-
rian ancestral karyotype.

The Florida manatee
The endangered Florida manatee is a subspecies of the
West Indian manatee (Trichechus manatus) in the order
Sirenia. Sirenians are often considered phylogenetic out-
liers. Despite similarities in adaptations, habitat, and
body shape, they have no evolutionary relationship with
the other orders of marine mammals. Extant sirenians are
the only herbivorous marine mammals and live in fresh,
brackish or marine habitats dispersed along tropical and
subtropical environments.

Previous cytogenetic reports on manatees
Solid stained chromosome studies were completed on a
limited number of individual manatees, establishing the
chromosome number as 2N = 48 for the Florida manatee
[9,10] and 2N = 56 for the Amazonian manatee (Tri-
chechus inunguis) [11]. Following solid staining, chromo-
some-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 Ama-
zonian manatee [13].


Comparisons of chromosome painting data provide an
independent test of the contrasting hypotheses on mam-
malian evolution and phylogeny. The research presented
here clarifies the phylogenetic position of the manatee
and tests the validity of the radical taxonomic assemblage
known as Afrotheria. The results are then compared to
other chromosome painting data in Afrotheria. In light of
the findings, the relationships within Afrotheria and the
alternative organizations of the ancestral eutherian karyo-
type are assessed.

Results
Examples of human chromosome paints (HSA) hybrid-
ized to manatee (TMA) metaphase chromosomes are
shown in Figure 1. Synteny was found intact in nine (4, 5,
6, 9, 11, 14, 17, 18 and 20) of the 22 human autosomal
and X chromosomes (Figure 2). Two hybridization signals
were evident on separate manatee chromosomes for ten
human chromosomes (1, 7, 8, 10, 12, 13, 15, 16, 21 and
22). The human 19 paint hybridized to three TMA chro-
mosomes (2, 12 and 14). Human chromosomes 2 and 3
were highly fragmented in the manatee genome and
painted four and five chromosomes, respectively (Table
1). Due to the small signals involved and the quality of
the metaphases, it was more difficult to assign the hybrid-
ization pattern for these two chromosomes. Human chro-
mosome paint 12 provided three signals on TMA 7, most
likely due to an inversion. Chromosome paints with peri-
centromeric signals on both arms of the same chromo-
some were considered as one signal. Centromere areas on
the manatee karyotype were not hybridized. The Y chro-
mosome was the only human probe that failed to provide
a signal in the manatee. Altogether, the human autosomal
chromosome paints and the X chromosome paint delim-
ited a total of 44 homologous segments in the manatee
genome. Human chromosome paints hybridized to 20
(15 unique) segments in the manatee genome: 1/15, 1/
19, 2/3 (twice), 3/7 (thrice), 3/13, 3/21, 5/21, 7/16, 8/22,
10/12 (twice), 11/20, 12/22 (thrice), 14/15, 16/19 and
18/19.

Discussion
The painting map of the manatee genome was compared
with results published on other Afrotheria taxa: aardvark,
elephant, elephant shrew and golden mole [14-17]. An
assessment of the associations found in each taxa are
shown in Table 1. All species have eight associations in
common (1/19, 3/21, 5/21, 7/16, 10/12, 12/22, 14/15
and 16/19). Five of these associations are considered
ancestral to all eutherians by most proposals (3/21, 7/16,
12/22 twice, 14/15 and 16/19). It appears that the associ-
ations 1/19 and 5/21 can be used to link afrotherian spe-
cies [14-16,18]. These associations provide cytogenetic
support, in agreement with molecular studies, that Afroth-
eria is a natural clade.


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'S

Itnti0

?t'% a
rjlf


Figure I
Examples of hybridizations in the manatee a) human 12, b)
human 13, c) human 14 in green and 15 in red d) human 17 in
green and 18 in red.



New chromosome painting data in Xenarthra anteaterss,
sloths and armadillos) are also informative towards the
ancestral eutherian karyotype. Of the four species studied,
Tamandua tetradactyla, Choloepus didactylus, C. hoffmanii
and Dasypus novemcinctus [18,19], only the anteater has a
1/19 association. It is not likely that this association is
homologous to Afrotheria, because the anteater has the
most highly rearranged karyotype known in Xenarthra
[181.

The manatee data indicate that the association 10/12/22
is most likely ubiquitous throughout Afrotheria. A combi-
nation HSA10p/12p/22q and a single HSA10q were
found in the aardvark and elephant karyotypes [14,17].
An apparently identical association was later found in the
elephant shrew and golden mole [15]. The question is,
whether this association is a third cytogenetic landmark
for the Afrotheria clade, or instead should be considered
part of the ancestral eutherian karyotype.

The entire 10/12/22 association appears to be present in
clades I, Afrotheria, and IV, Laurasiatheria, only partially
present in clade II, Xenarthra (10/12), and absent in clade
III, Euarchontoglires (primates, rabbits, rodents, tree
shrews and flying lemurs). Carnivores have a homologous
10/12/22 association to Afrotheria, as demonstrated by
reciprocal chromosome painting [20,21]. Eulipotyphla
(shrews, solenodons, moles, hedgehogs, and Nesophontes)
also have the 10/12/22 association [19,22]. Chromosome
painting data in Xenarthra show that a 10/12 association


is present in the armadillo (D. novemcinctus) [ 181. To date,
the 10/12 association has been found in three of the four
eutherian mammal clades. Yet, there is no reciprocal
painting in Xenarthra to prove that the 10/12 association
is truly homologous to that found in Afrotheria. Several
hypotheses can be developed with different implications
if Afrotheria or Xenarthra is considered basal. If Afrotheria
is basal, the occurrence of 10/12/22 in clades I and IV
would suggest that this association is part of the ancestral
eutherian karyotype with a subsequent, independent loss
in clades II and III. The occurrence of the 10/12/22 asso-
ciation clades I and IV, could be considered a phyloge-
netic link. Alternatively, the association could have been
independently acquired in the two clades. If Xenarthra is
basal, this association could have originated in Afrotheria
and was then lost in clade III.

Association 3/13 was found in the manatee, elephant and
elephant shrew. However, there are no reciprocal painting
data between human and manatee or human and ele-
phant shrew. Therefore, it is not possible to confirm that
the 3/13 association is homologous (involves the same
segments of both chromosomes 3 and 13). In view of the
afrotherian molecular data, this association was inde-
pendently derived in the Macroscelidae (elephant shrews)
and Paenungulata phylogenetic lineages [8].

Support for the Tethytheria and Paenungulata assemblage
Before the advent of molecular studies, some morpholo-
gists placed sirenians, elephants and hyraxes under Ungu-
lata. Elephants and sirenians were grouped together in
Tethytheria, while hyraxes were placed in Phenacodonta
along with perissodactyls [23]. Results in molecular stud-
ies are inconsistent and fail to resolve the Paenungulate
trifurcation [8] and some data do not support Tethytheria
[2,24-26]. Mitochondrial genome analyses do support
Tethytheria, but exclude Hyracoidea [1]. SINE insertion
data produced incongruent phylogenetic relationships
within Paenungulata, most likely due to a rapid diver-
gence from a highly polymorphic last common ancestor
[27].

The chromosome mapping data strongly support Tethyth-
eria sirenianss and elephants) and implies support for the
clade Paenungulata (Sirenia, Proboscidea, and Hyracoi-
dea). There appear to be four derived associations linking
elephants with manatees: 2/3, 3/13, 8/22 and 18/19. HSA
4/8p was not present in the manatee and may represent a
derived trait of Paenungulata. Both publications on the
elephant indicate that this association is also lacking
[14,17]. It is possible that the 4/8 association went unde-
tected in our study, as well as in elephants. Although, the
widespread occurrence of the 4/8 association in all mam-
mals, outside of elephants and most primates, lends cre-
dence to its inclusion in the ancestral eutherian karyotype.


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5 6



1r .II| l=I 4


11 12 13 14 15


321
20


5 19 6 11 4
19 5
I 2 3 4 5

-12 -
10 15 -
10
112 1 3 j2
6 7 8 9 10


1 19 18 118 1
10o 13 1 2 3 11 12 13 14 15
21 22 23 Y 12 8 1
3 8 33 117
son 4 S 6 16 17 18 19 20
a un4 s 6 In


m 19 MM mo10 13 I2 X
human chromosome color key 23 X Y






Figure 2
The karyotype of the manatee is shown to the left and the color coded idiogram to the right (modified from Gray et al. 2002).
Manatee chromosomes are numbered below and human chromosome homology is shown laterally.


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Table I:


2n I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 21 22


AEK
manatee
golden mole
elephant shrew
aardvark
elephant


Number of segments homologous to human chromosome found in Afrotheria species. The taxa in the first, left column: AEK = ancestral eutherian
karyotype [14, 16, 40]. The second column list the 2n, diploid numbers for each species and the remaining columns refer to signals found for each
human chromosome. The number in brackets refers to higher number of hybridization signals due to pericentric inversions.


It would be useful to test these hypotheses with rock hyrax
chromosome painting data.

Branching order in Afrotheria
The branching order within Afrotheria has not reached a
consensus. Some authors have viewed Macroscelidae, the
elephant shrews, as the most basal and early divergent
order within Afrotheria [2,28]. However, Murphy et al.
(2001) placed the triumvirate of sirenians, elephants and
hyraxes (Paenungulata) as basal, verified by additional
molecular data [1,3,29]. It is difficult to determine which
order is most basal because sirenians and elephants, like
other afrotherian species, have fairly derived karyotypes.

According to Robinson et al. (2003), associations 2/8, 3/
20 and 10/17 link elephant shrews, golden moles/tenrecs
and aardvarks. Only the association 2/8 is present in all
three. Recently, the association 2/8 was also found in ant-
eater (T. tetradactyla), sloth (Choloepus didactylus) and pan-
golin (Manis javanica) [18,19]. Associations 3/20 and 10/
17 are lacking in golden moles/tenrecs. Murphy et al.
(2004) proposed that the associations 3/20 and 10/17
were probably lost in golden moles/tenrecs. No reciprocal
painting was done in elephant shrews or golden moles/
tenrecs and it is therefore unknown if these associations
are actually homologous. There is weak cytogenetic evi-
dence linking elephant shrews and golden moles/tenrecs.
An alternate hypothesis might be a sister relationship
between elephant shrews and aardvarks. Perhaps a rapid
divergence in elephant shrews, golden moles/tenrecs and
aardvarks also resulted in limited phylogenetic signals for
these chromosome associations.

The root of the Eutherian tree
Although the super-order assemblies appear well estab-
lished, the most basal position on the eutherian tree has
not been determined with certainty [2,25,30]. Afrotheria
and Xenarthra are the two oldest eutherian clades and
probably emerged from the Southern Hemisphere in
excess of 100 million years ago [31,32]. Molecular dating
and biogeography have provided evidence that crown-
group Eutheria may have their most recent common


ancestry in the Southern Hemisphere (Gondwana) [32].
The other two clades (Laurasiatheria and Euarchontog-
lires) can be grouped as Boreoeutheria [33].

There are currently three hypotheses for the root of the
eutherian tree. Most discussions from molecular studies
place emphasis on either Afrotheria or Xenarthra as the
most basal clade [25,34]. A third hypothesis states that the
ancestral eutherian karyotype is a combination of both
clades. This hypothesis cannot be completely ruled out
and is preferred in some studies [35,36]. However, the
suite of derived chromosomal associations found in all
studied Afrotheria argues against the hypothesis that a
combination of the two clades is basal to the eutherians.

Recently, a report on retroelements gives support for the
hypothesis that Xenarthra is the sister group to all other
placentals [37]. Indeed, new cytogenetic comparisons
show that the proposed ancestral eutherian karyotype is
essentially conserved in Xenarthra, specifically in the two-
toed sloth (Choloepus hoffmanii) [16]. These two studies
should be given attention because both take into consid-
eration rare genomic events in which convergence is par-
ticularly limited. The conserved xenarthran karyotype
may well be indicative of their phylogenomic position
among eutherians. However, an essential point is that all
reconstructions of the ancestral eutherian karyotype are
preliminary until a relevant outgroup is studied with chro-
mosome painting. A taxonomically rich array of species
supported by appropriate out-groups is vital to the recon-
struction of mammalian genome evolution. The defi-
ciency of comparative chromosome painting data
between eutherians and marsupials is a severe limitation
on attempts to delineate the mammalian ancestral
genome. The analyses of other afrotherians, xenarthrans
and marsupials may clarify these unresolved questions.

Conclusion
The chromosome painting data presented here leave little
doubt that Tethytheria is a clade within Afrotheria and
implies support for the Paenungulata assemblage. Recent
retroposon data also confirmed Paenungulata, but could


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not resolve the phylogenetic relationships among ele-
phants, sirenians and hyraxes [27]. It is generally appreci-
ated that characters with high evolutionary rates provide
good phylogenetic resolution. Afrotherian karyotypes
demonstrate high rates of chromosome evolution and
numerous derived inter-chromosomal rearrangements
link elephants and manatees. It is therefore likely that
additional chromosome painting in rock hyraxes could
shed light on the divergence sequence and resolve the Pae-
nungulata trichotomy.

Methods
Chromosome preparations of a male Florida manatee
(Trichechus manatus latirostris, TMA) were obtained from
peripheral blood mononuclear cells (PBMCs) and pri-
mary fibroblast cartilage cell culture. Cells were cultured
in RPMI 1640 (Hyclone) supplemented with 20% fetal
bovine serum (FBS), L-glutamine (0.01%) and gen-
tamicin (25 jig/ml). PBMCs were incubated in-vivo using
phytohemagglutinin (PHA, 0.25 mg/mL) as a mitotic
stimulant for 72 to 96 hr at 36C in 5% carbon dioxide,
95% air and 100% relative humidity. 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.

Human chromosome paints were obtained as previously
described by chromosome flow sorting followed by
degenerate oligonucleotide primed PCR amplification
[38,39]. Paints were labeled with either biotin-dUTP, dig-
oxigen-dUTP (both from Roche Applied Science) or Spec-
trum Orange-dUTP (Vysis).

Interspecific in-situ hybridizations of Florida manatee
chromosomes with human probes were performed with
300 to 500 ng of each biotin-labeled probe, 10 jig of
human Cot-1 DNA and 5 jig of ssDNA. The mixture was
precipitated and dissolved in 13-15 jil of hybridization
mixture (formamide 50%, dextran sulfate 10%, 2 x SSC).
Direct labeling with Spectrum Orange followed a Nick
Translation protocol (Vysis) using 1 [ig of each amplified


human DNA probe, 0.2 mM Spectrum Orange and 25 jig
each of human and manatee Cot-1 DNA (Applied Genet-
ics Laboratories, Inc.). The mixture was precipitated and
dissolved in 10 il distilled water. Approximately 300 ng
of probe from this mixture were dissolved in 10.5 1il
Hybrizol VII (Q-BIOgene) and 0.75 jig each of human
and manatee Cot-1 DNA.

The labeled probe mixture was denatured at 800C for 10
min and reannealed at 370 C for 90 min before hybridiza-
tion. Slides were aged at 370C for 30 min followed by
dehydration in a room temperature 70, 80, 90, and 100%
ethanol series. The DNA was denatured in 70% forma-
mide/2 x SSC, at 65C for 90-120 s, and quenched in an
ice-cold ethanol series. Hybridization was carried out in a
humidity chamber at 37 C for five days. Post-hybridiza-
tion washes followed standard procedures at 40 C. Biotin
detection was performed with avidin-conjugated FITC
(Vector) for 45 min at 37C. Counterstaining was per-
formed with DAPI (0.8 ng/jl) for 10 min and the slides
were mounted with antifade (100 mg p-phenylenedi-
amine in 80 ml glycerine, 20 ml PBS, pH 8).

Analyses were performed under a Zeiss Axiophot 2 or Axi-
oskop fluorescence microscope coupled with a CCD cam-
era (Photometrics), and images were captured with the
Smart Capture software (Digital Scientific Inc.).

Authors' contributions
RS and RZ conceived and designed the experiments. MK,
SB, TD and RS performed the experiments. BG, MK, RZ,
GS and PM prepared and contributed reagents/cell cul-
tures/analysis tools. RS, MK and SB analysed the data. RS,
MK and PM wrote the paper. All author read and
approved the final manuscript.

Acknowledgements
RS was supported by a grant "Mobility of Italian and foreign researchers
residing abroad" from MIUR (Ministero Italiano della Universita' e della
Ricerca). The U.S. Geological Survey and the University of Florida College
of Veterinary Medicine provided support to MK. Samples of manatee tissue
were collected under the U.S. Fish and Wildlife Service federal research


Table 2:


1/19 2/3 2/8 3/13 3/20 3/21 4/8 5/21


X X
x x
x x
X X
X X


X X
X X X
X X

X
X


7/16 8/22 10/12 10/17 12/22 14/15 16/19 18/19 total


?
x
X
X
X X
X X
x x
x x


x x
X X
x x
X X
X
X


6-7
21
14
20
X 17
X 15


Chromosomal associations found in two or more Afrotheria taxa. AEK = ancestral eutherian karyotype [14, 16, 40]. Associations were counted
only once to derive the total.



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AEK
elephant shrew
golden mole
Aardvark
Elephant
Manatee


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permit MA791721 issued to the USGS, Sirenia Project. Many thanks for the
expertise and support of the UF Cytogenetics Laboratory staff.


References
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