144 research outputs found
DOG-SPOT database for comprehensive management of dog genetic research data
Research laboratories studying the genetics of companion animals have no database tools specifically designed to aid in the management of the many kinds of data that are generated, stored and analyzed. We have developed a relational database, "DOG-SPOT," to provide such a tool. Implemented in MS-Access, the database is easy to extend or customize to suit a lab's particular needs. With DOG-SPOT a lab can manage data relating to dogs, breeds, samples, biomaterials, phenotypes, owners, communications, amplicons, sequences, markers, genotypes and personnel. Such an integrated data structure helps ensure high quality data entry and makes it easy to track physical stocks of biomaterials and oligonucleotides
SINE retrotransposons import polyadenylation signals to 3\u27UTRs in dog (Canis familiaris).
BACKGROUND: Messenger RNA 3\u27 untranslated regions (3\u27UTRs) control many aspects of gene expression and determine where the transcript will terminate. The polyadenylation signal (PAS) AAUAAA (AATAAA in DNA) is a key regulator of transcript termination and this hexamer, or a similar sequence, is very frequently found within 30 bp of 3\u27UTR ends. Short interspersed element (SINE) retrotransposons are found throughout genomes in high copy numbers. When inserted into genes they can disrupt expression, alter splicing, or cause nuclear retention of mRNAs. The genomes of the domestic dog and other carnivores carry hundreds of thousands of Can-SINEs, a tRNA-related SINE with transcription termination potential. Because of this we asked whether Can-SINEs may terminate transcript in some dog genes.
RESULTS: Each of the dog\u27s nine Can-SINE consensus sequences carry an average of three AATAAA PASs on their sense strands but zero on their antisense strands. Consistent with the idea that Can-SINEs can terminate transcripts, we find that sense-oriented Can-SINEs are approximately ten times more frequent at 3\u27 ends of 3\u27UTRs compared to further upstream within 3\u27UTRs. Furthermore, the count of AATAAA PASs on head-to-tail SINE sequences differs significantly between sense and antisense-oriented retrotransposons in transcripts. Can-SINEs near 3\u27UTR ends are likely to carry an AATAAA motif on the mRNA sense strand while those further upstream are not. We identified loci where Can-SINE insertion has truncated or altered a 3\u27UTR of the dog genome (dog 3\u27UTR) compared to the human ortholog. Dog 3\u27UTRs have peaks of AATAAA PAS frequency at 28, 32, and 36 bp from the end. The periodicity is partly explained by TAAA(n) repeats within Can-SINE AT-rich tails. We annotated all repeat-masked Can-SINE copies in the Boxer reference genome and found that the young SINEC_Cf type has a mode of 15 bp length for target site duplications (TSDs). All dog Can-SINE types favor integration at TSDs beginning with A(4).
CONCLUSION: Dog Can-SINE retrotransposition has imported AATAAA PASs into gene transcripts and led to alteration of 3\u27UTRs. AATAAA sequences are selectively removed from Can-SINEs in introns and upstream 3\u27UTR regions but are retained at the far downstream end of 3\u27UTRs, which we infer reflects their role as termination sequences for these transcripts
The IGF1 small dog haplotype is derived from Middle Eastern gray wolves
Abstract Background A selective sweep containing the insulin-like growth factor 1 (IGF1) gene is associated with size variation in domestic dogs. Intron 2 of IGF1 contains a SINE element and single nucleotide polymorphism (SNP) found in all small dog breeds that is almost entirely absent from large breeds. In this study, we surveyed a large sample of grey wolf populations to better understand the ancestral pattern of variation at IGF1 with a particular focus on the distribution of the small dog haplotype and its relationship to the origin of the dog. Results We present DNA sequence data that confirms the absence of the derived small SNP allele in the intron 2 region of IGF1 in a large sample of grey wolves and further establishes the absence of a small dog associated SINE element in all wild canids and most large dog breeds. Grey wolf haplotypes from the Middle East have higher nucleotide diversity suggesting an origin there. Additionally, PCA and phylogenetic analyses suggests a closer kinship of the small domestic dog IGF1 haplotype with those from Middle Eastern grey wolves. Conclusions The absence of both the SINE element and SNP allele in grey wolves suggests that the mutation for small body size post-dates the domestication of dogs. However, because all small dogs possess these diagnostic mutations, the mutations likely arose early in the history of domestic dogs. Our results show that the small dog haplotype is closely related to those in Middle Eastern wolves and is consistent with an ancient origin of the small dog haplotype there. Thus, in concordance with past archeological studies, our molecular analysis is consistent with the early evolution of small size in dogs from the Middle East. See associated opinion by Driscoll and Macdonald: http://jbiol.com/content/9/2/1
Determination of the Deep Inelastic Contribution to the Generalised Gerasimov-Drell-Hearn Integral for the Proton and Neutron
The virtual photon absorption cross section differences [sigma_1/2-sigma_3/2]
for the proton and neutron have been determined from measurements of polarised
cross section asymmetries in deep inelastic scattering of 27.5 GeV
longitudinally polarised positrons from polarised 1H and 3He internal gas
targets. The data were collected in the region above the nucleon resonances in
the kinematic range nu < 23.5 GeV and 0.8 GeV**2 < Q**2 < 12 GeV**2. For the
proton the contribution to the generalised Gerasimov-Drell-Hearn integral was
found to be substantial and must be included for an accurate determination of
the full integral. Furthermore the data are consistent with a QCD
next-to-leading order fit based on previous deep inelastic scattering data.
Therefore higher twist effects do not appear significant.Comment: 6 pages, 3 figures, 1 table, revte
The Flavor Asymmetry of the Light Quark Sea from Semi-inclusive Deep-inelastic Scattering
The flavor asymmetry of the light quark sea of the nucleon is determined in
the kinematic range 0.02<x<0.3 and 1 GeV^2<Q^2<10 GeV^2, for the first time
from semi-inclusive deep-inelastic scattering. The quantity
(dbar(x)-ubar(x))/(u(x)-d(x)) is derived from a relationship between the yields
of positive and negative pions from unpolarized hydrogen and deuterium targets.
The flavor asymmetry dbar-ubar is found to be non-zero and x dependent, showing
an excess of dbar over ubar quarks in the proton.Comment: 7 Pages, 2 figures, RevTeX format; slight revision in text, small
change in extraction of dbar-ubar and comparison with a high q2
parameterizatio
Observation of a Coherence Length Effect in Exclusive Rho^0 Electroproduction
Exclusive incoherent electroproduction of the rho^0(770) meson from 1H, 2H,
3He, and 14N targets has been studied by the HERMES experiment at squared
four-momentum transfer Q**2>0.4 GeV**2 and positron energy loss nu from 9 to 20
GeV. The ratio of the 14N to 1H cross sections per nucleon, known as the
nuclear transparency, was found to decrease with increasing coherence length of
quark-antiquark fluctuations of the virtual photon. The data provide clear
evidence of the interaction of the quark- antiquark fluctuations with the
nuclear medium.Comment: RevTeX, 5 pages, 3 figure
Observation of a Single-Spin Azimuthal Asymmetry in Semi-Inclusive Pion Electro-Production
Single-spin asymmetries for semi-inclusive pion production in deep-inelastic
scattering have been measured for the first time. A significant target-spin
asymmetry of the distribution in the azimuthal angle phi of the pion relative
to the lepton scattering plane was observed for pi+ electro-production on a
longitudinally polarized hydrogen target. The corresponding analyzing power in
the sin(phi) moment of the cross section is 0.022 +/- 0.005 +/- 0.003. This
result can be interpreted as the effect of terms in the cross section involving
chiral-odd spin distribution functions in combination with a time-reversal-odd
fragmentation function that is sensitive to the transverse polarization of the
fragmenting quark.Comment: 5 pages of RevTex, 3 ps figures, 2 table
Measurement of Angular Distributions and R= sigma_L/sigma_T in Diffractive Electroproduction of rho^0 Mesons
Production and decay angular distributions were extracted from measurements
of exclusive electroproduction of the rho^0(770) meson over a range in the
virtual photon negative four-momentum squared 0.5< Q^2 <4 GeV^2 and the
photon-nucleon invariant mass range 3.8< W <6.5 GeV. The experiment was
performed with the HERMES spectrometer, using a longitudinally polarized
positron beam and a ^3He gas target internal to the HERA e^{+-} storage ring.
The event sample combines rho^0 mesons produced incoherently off individual
nucleons and coherently off the nucleus as a whole. The distributions in one
production angle and two angles describing the rho^0 -> pi+ pi- decay yielded
measurements of eight elements of the spin-density matrix, including one that
had not been measured before. The results are consistent with the dominance of
helicity-conserving amplitudes and natural parity exchange. The improved
precision achieved at 47 GeV,
reveals evidence for an energy dependence in the ratio R of the longitudinal to
transverse cross sections at constant Q^2.Comment: 15 pages, 15 embedded figures, LaTeX for SVJour(epj) document class
Revision: Fig. 15 corrected, recent data added to Figs. 10,12,14,15; minor
changes to tex
Measurement of Longitudinal Spin Transfer to Lambda Hyperons in Deep-Inelastic Lepton Scattering
Spin transfer in deep-inelastic Lambda electroproduction has been studied
with the HERMES detector using the 27.6 GeV polarized positron beam in the HERA
storage ring. For an average fractional energy transfer = 0.45, the
longitudinal spin transfer from the virtual photon to the Lambda has been
extracted. The spin transfer along the Lambda momentum direction is found to be
0.11 +/- 0.17 (stat) +/- 0.03 (sys); similar values are found for other
possible choices for the longitudinal spin direction of the Lambda. This result
is the most precise value obtained to date from deep-inelastic scattering with
charged lepton beams, and is sensitive to polarized up quark fragmentation to
hyperon states. The experimental result is found to be in general agreement
with various models of the Lambda spin content, and is consistent with the
assumption of helicity conservation in the fragmentation process.Comment: 8 pages, 3 figures; new version has an expanded discussion and small
format change
Beam-Induced Nuclear Depolarisation in a Gaseous Polarised Hydrogen Target
Spin-polarised atomic hydrogen is used as a gaseous polarised proton target
in high energy and nuclear physics experiments operating with internal beams in
storage rings. When such beams are intense and bunched, this type of target can
be depolarised by a resonant interaction with the transient magnetic field
generated by the beam bunches. This effect has been studied with the HERA
positron beam in the HERMES experiment at DESY. Resonances have been observed
and a simple analytic model has been used to explain their shape and position.
Operating conditions for the experiment have been found where there is no
significant target depolarisation due to this effect.Comment: REVTEX, 6 pages, 5 figure
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