Twenty years ago the field of ancient DNA was launched with the
publication of two short mitochondrial (mt) DNA sequences from a single
quagga (Equus quagga) museum skin, an extinct South African equid
(Higuchi et al. 1984). This was the first extinct species from
which genetic information was retrieved. We have isolated DNA from
eight quaggas and an extinct population of the plains zebra (Equus
burchelli burchelli). We show that the quagga displayed little genetic
diversity and very recently diverged from the plains zebra, probably
during the penultimate glacial maximum. This emphasizes the importance
of Pleistocene climate changes for phylogeographic patterns in African
as well as Holarctic fauna. This work is in collaboration with Scott Glaberman (Graduate Student EEB) and many US and international scientists.
Scott Glaberman (EEB graduate student) sampling a bone for DNA analysis from a Quagga (extinct zebra species) bone from the Peabody museum at Yale.
Publication: Leonard, J.A., N. Rohland, S. Glaberman , R. C. Fleischer, S. Pääbo, A. CACCONE and M. Hofreiter. 2005. How a Zebra Lost its Stripes: 20 Years of Ancient DNA and the Origin of the Quagga. Biology Letters 1(3): 291-295.
Extinct dwarf elephants from the Mediterranean islands
During the Pleistocene pygmy elephantids, some only a quarter of their
ancestor’s size, were present on some Mediterranean islands until about
10,000 years ago (y.a.) Using a whole genomic amplification method new
to the “ancient DNA world” we were able to retrieve DNA fragments from
4,200 to 800,000 y.a. samples from island and mainland pygmy and
normal-sized forms. Our results challenge the prevailing view that
pygmy elephantids of the Mediterranean originated exclusively from
Elephas, suggesting independent histories of dwarfism and the presence
of both pygmy mammoth and elephant-like taxa on the eastern
Mediterranean islands. When a new ancient DNA sequence is retrieved, it
is often claimed that it will rewrite the textbooks of the organism it
came from. This holds true for this study as well. This work is in
collaboration with Scott Glaberman (Graduate Student EEB), Nikos Poulakakis (Natural History Museum of Crete), D. Reese (Yale Peabody Museum), scientists from the University of Crete and the Crete Natural History Museum.
Poulakakis, N., A. Parmakelis, P. Lymberakis, M. Mylonas, E. Zouros, D. S. Reese, S. Glaberman, A. CACCONE. Ancient DNA forces reconsideration of evolutionary history of Mediterranean pygmy elephantids. Biology Letters, 2 451-454.
Extinct giant and dwarf deer of Crete
One of the most interesting problems in paleontology is the occurrence in the Quaternary of a
rich fauna of endemic dwarf and giant species of vertebrates on several
Mediterranean islands, including Sicily, Sardinia, Malta, Tilos,
Cyprus, and Crete. In Crete, elephants, hippos, cervids and murids
changed; generally, smaller animals increased in size whereas larger
animals decreased in size. This project focuses on one of these groups,
the deer. Their evolution on Crete is more complex, with greater
variation in size and morphology than in any other vertebrates that
made it to the island. Different named taxa (5-8 different species)
ranged in size from animals as large as a caribou or a small elk to
specimens similar in size to a dik-dik or a muntjac. We are proposing
to take advantage of the ability to of extract DNA from dated dental
and bone remains to produce a molecular phylogeny of the extinct
cervids of Crete. For comparative purposes, we also will include DNA
sequences of several mainland extinct and extant species. This
phylogenetic approach will help us address a series of questions
regarding their phyletic relations with the mainland fauna, and the
patterns and timing of colonization of Crete (i.e., Are the different
named taxa distinct phyletic lineages? Which colonization model do the
genetic data support? Did the lineage(s) of Cretan deer originate from
one or several mainland species? This work is in collaboration with Nikos Poulakakis, D. Reese (Yale Peabody Museum) and the group of R. Fleischer from the Smithsonian Museum of Natural History.
