Tarsus determination in Drosophila melanogaster

Authors: A. Percival-Smith, W.A. Teft and J.L. Barta
Journal: Genome – 48(4):712-721 (2005)

Arista versus tarsus determination is well investigated in Drosophila, yet it remains unresolved whether Antennapedia (ANTP) cell autonomously or noncell autonomously determines tarsus identity and whether Sex combs reduced (SCR) is the HOX protein required for normal tarsus determination. Three observations rule out a cell autonomous role for ANTP in tarsus determination. (i) Clonal ectopic overexpression of ANTP did not repress the expression of the arista determining protein Homothorax (HTH) in early 3rd stadium antennal imaginal discs. (ii) Clonal ectopic expression of ANTP did not transform the arista to a tarsus. (iii) Ectopic overexpression of ANTP, Labial (LAB), Deformed (DFD), SCR, Ultrabithorax (UBX), Abdominal-A (ABD-A), or Abdominal-B (ABD-B), using the dppGAL4 driver, resulted in arista-to-tarsus transformations, and repressed HTH/Extradenticle (EXD) activity noncell autonomously in early 3rd stadium antennal imaginal discs. SCR may not be the HOX protein required for normal tarsus determination, because co-ectopic expression of Proboscipedia (PB) inhibited the arista-to-tarsus transformations induced by ectopic expression of DFD, SCR, ANTP, UBX, ABD-A, and ABD-B. The proposal that SCR is the HOX protein required for normal tarsus determination is dependent on SCR being the sole target of PB suppression, which is not the case. Therefore, the possibility exists that normal tarsus determination is HOX independent.

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Osteocalcin protein sequences of Neanderthals and modern primates

Authors: Christina M. Nielsen-Marsha,b, Michael P. Richardsa,c, Peter V. Hauschkad, Jane E. Thomas-Oatese, Erik Trinkausf, Paul B. Pettittg, Ivor Karavanic´h, Hendrik Poinar, and Matthew J. Collins
Journal: PNAS | vol. 102, no. 12, 4409–4413

We report here protein sequences of fossil hominids, from two Neanderthals dating to ~75,000 years old from Shanidar Cave in Iraq. These sequences, the oldest reported fossil primate protein sequences, are of bone osteocalcin, which was extracted and sequenced by using MALDI-TOF/TOF mass spectrometry. Through a combination of direct sequencing and peptide mass mapping, we determined that Neanderthals have an osteocalcin amino acid sequence that is identical to that of modern humans. We also report complete osteocalcin sequences for chimpanzee (Pan troglodytes) and gorilla (Gorilla gorilla gorilla) and a partial sequence for orangutan (Pongo pygmaeus), all of which are previously unreported. We found that the osteocalcin sequences of Neanderthals, modern human, chimpanzee, and orangutan are unusual among mammals in that the ninth amino acid is proline (Pro-9), whereas most species have hydroxyproline (Hyp-9). Posttranslational hydroxylation of Pro-9 in osteocalcin by prolyl-4-hydroxylase requires adequate concentrations of vitamin C (L-ascorbic acid), molecular O2, Fe2+, and 2-oxoglutarate, and also depends on
enzyme recognition of the target proline substrate consensus sequence Leu-Gly-Ala-Pro-9-Ala-Pro-Tyr occurring in most mammals.
In five species with Pro-9–Val-10, hydroxylation is blocked, whereas in gorilla there is a mixture of Pro-9 and Hyp-9. We suggest that the absence of hydroxylation of Pro-9 in Pan, Pongo, and Homo may reflect response to a selective pressure related to a decline in vitamin C in the diet during omnivorous dietary
adaptation, either independently or through the common ancestor of these species.

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Long-Term Survival of Ancient DNA in Egypt: Response to Zink and Nerlich (2003)

Authors: M.T.P. Gilbert, I. Barnes, M.J. Collins, C. Smith, J. Eklund, J. Goudsmit, H. Poinar and A. Cooper
Journal: American journal of physical anthropology (2005) – Notes and comment

Using the degradation of papyrus chloroplast DNA as a general model of molecular degradation in Egypt, Marota et al. (2002) proposed that PCR-amplifiable DNA is unlikely to survive in ancient Egyptian specimens. If correct, this suggests that the numerous studies claiming to have successfully amplified host and/or pathogen DNA from ancient Egyptians (e.g., Zink et al., 2000a,b, 2001, 2003a,b) must be reevaluated.

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Long-Term Survival of Ancient DNA in Egypt: Response to Zink and Nerlich (2003)

Authors: M.T.P. Gilbert, I. Barnes, M.J. Collins, C. Smith, J. Eklund, J. Goudsmit, H. Poinar and A. Cooper
Journal: American journal of physical anthropology (2005) – Notes and comment

Using the degradation of papyrus chloroplast DNA as a general model of molecular degradation in Egypt, Marota et al. (2002) proposed that PCR-amplifiable DNA is unlikely to survive in ancient Egyptian specimens. If correct, this suggests that the numerous studies claiming to have successfully amplified host and/or pathogen DNA from ancient Egyptians (e.g., Zink et al., 2000a,b, 2001, 2003a,b) must be reevaluated.

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