how the sequence of DNA is analysed in a sample of hair?

Question

i have been studying about the sequences od DNA but i have seen in many detective programmes that the experts of the foreinsic sciences find out the type of DNA from a hair follicle. how is it done? i am very curious to know. can anybody tell me the proper answer for this?

Answer 1

During the course of a criminal investigation, many types of physical evidence are encountered. One of the most common is hair evidence. The identification and comparison of human and animal hairs can be helpful in demonstrating physical contact with a suspect, victim, and crime scene. Hairs can provide investigators with valuable information for potential leads.

Until recently, the comparison microscope was considered the only reliable tool for the identification and comparison of the microscopic characteristics found in hair. Today, nuclear and mitochondrial DNA (mtDNA) testing can provide additional information that can influence the value of microscopic examinations. When the microscope is coupled with DNA technologies, the combination of these technologies profoundly affects the way forensic scientists, investigators, and prosecutors view hair evidence.

Although DNA technologies may add significant information to hair evidence recovered at a crime scene, the first step necessary in the analytical process is the identification and comparison of human and animal hairs. This revision of the 1977 Microscopy of Hairs: A Practical Guide and Manual by John W. Hicks is intended to introduce hair evidence to the forensic examiner and to provide a foundation for its proper identification and comparison.

For full detailed study diagrams and explanation hit the site :-
http://www.fbi.gov/hq/lab/fsc/backissu/jan2004/research/2004_01_research01b.htm

Answer 2

the hair must contain the follicle, not just the hair shaft. The DNA is multiplied by using the polymerase chain method, then electrophoresed to give the unique pattern.

Answer 3

gray hair does not isn't constantly linked with age as maximum human beings have confidence. i might propose taking him to make sure a physician through fact this is a consequence of a b12 definciency or a thyroid subject.

Answer 4

hair follicular cells help in detecting and identifying the DNA

Answer 5

Magazine
R463
Correspondence
Ancient mitochondrial
DNA
from hair
M. Thomas P. Gilbert1,2, Andrew
S. Wilson3,4, Michael Bunce1,
Anders J. Hansen5, Eske
Willerslev5, Beth Shapiro1,
Thomas F.G. Higham6, Michael P.
Richards7, Tamsin C. O’Connell6,
Desmond J. Tobin4, Robert C.
Janaway3 and Alan Cooper1*
The DNA content of hair [1,2] is
typically low compared to other
tissues, as hair cells undergo
dehydration and catabolic
breakdown of nucleic acids and
organelles during keratinisation
[3]. As a consequence, ancient
hair specimens have not been
widely used as a source of
ancient DNA. However,
mitochondrial DNA (mtDNA) has
been extracted from degraded
and old hair samples, including
burnt specimens [4], 100-yearold
Native American samples [5],
and wool from a 9,400 year old
Bighorn sheep [6]. We have
investigated the potential of hair
as an aDNA source by analyzing
DNA survival in 12 samples
which range from 60 to >64,800
years of age and their
susceptibility to contamination
with modern DNA.
mtDNA was successfully
amplified, cloned, and sequenced
from 10 of the 12 hair samples
following decontamination
procedures (Table 1). DNA was
quantified using Quantitative
Real-Time PCR in a subset of the
samples (Table 1). The survival of
high copy numbers of 16S DNA
from the 3,000 year-old Pazyryk
horse hairs is consistent with the
observation that DNA survives
longer at sub-zero temperatures
[7]. Of greater surprise was the
persistence of high numbers of
16S and Control Region DNA
molecules in hairs sampled from a
bison mummy 14C dated to
>64,800 years. This result was
independently replicated and
extends the time frame from
which authentic DNA has been
retrieved from hair by at least
seven-fold, placing it on a par
with the oldest authentic DNA
retrieved from bones and teeth
[8]. No nuclear DNA could be
amplified from the bison hair,
consistent with observations of
modern hair samples [1,9]. It is
probably significant that the bison
hairs are exceedingly well
preserved — the atomic carbon to
nitrogen ratio (3.47) is similar to
modern mammal hair [10,11] and
histological analysis of the
specimen demonstrates the only
structural modifications to be
slight cuticular loss and adherent
deposits (Supplemental data).
Amplifiable mtDNA was also
present in all except two hair
samples preserved at warmer
temperatures, although at lower
levels than the animal hairs.
Several studies comment on the
negative effect of various hair
treatments (i.e.,
coloring/bleaching) on DNA
survival [5,12,13], and it is
possible that these two samples
were artificially treated pre or
post mortem. Hypervariable
Region 1 (HVR1) sequences
obtained from hair of Andaman
Island specimens are consistent
with previous dental studies [14];
in contrast, several hair samples
attributed to Sir Isaac Newton
each yielded different HVR1
sequences. The cloned PCR
products indicated that each
source of hair contained only a
single HVR1 sequence, but one
that did not match sequences
from the other samples. As each
hair source has been handled on
numerous occasions, it seems
unlikely that only a single
contaminant sequence would
survive per hair sample. However,
we naturally cannot remove all
reasonable doubts that they may
still represent DNA
contamination. We therefore
suggest that at least three of the
hair samples do not originate
from Sir Isaac Newton. This
hypothesis is in agreement with
the conclusions of separate
isotope analyses performed on
the samples (A. Wilson
unpublished data).
Many ancient specimens used
for DNA analyses are difficult, if
not impossible, to decontaminate
from exogenous sources of DNA
[8]. Surprisingly, although the DNA
extracted from each animal hair
sample was tested for
contaminant human HVR1
sequences, none were detected. A
similar lack of contamination
appeared to apply to the human
hair samples; no sequence
variation was observed among
cloned sequences (bar that which
could be attributed to post
mortem DNA damage [15]), even
though the specimens have been
handled multiple times by multiple
individuals during their
conservation history. These
results suggest that hairs are
either impermeable to sources of
contaminant DNA (e.g., human
sweat), or can be easily
decontaminated (e.g. by bleach)
to remove exogenous DNA. It is
possible that this behavior is due
to the hydrophobic nature of
keratin, which comprises most of
the hair shaft. The low quantities
of free water associated with the
keratin-packed hair cells may also
reduce hydrolytic damage of the
DNA. Such a scenario would
explain the extended and high
concentrations of DNA surviving in
the bison and horse hair, as well
as the relatively low levels of
hydrolytic damage-induced
lesions among the cloned DNA.
The successful amplification of
high yields of uncontaminated
mtDNA indicate that hair
represents a useful and underutilized
source of aDNA. While the
recovery of nuclear DNA from
ancient hair is unlikely, this
limitation also has the advantage
of preventing the unintentional
amplification of nuclear copies of
mitochondiral sequences, which
have proved problematic [8].
Furthermore, a preferential use of
hair (and potentially feathers and
scales) for genetic analyses would
minimise the destruction of
valuable historical and
archaeological specimens caused
by sampling of teeth or bones.
Supplemental data
Supplemental data containing
experimental procedures are
available at http://www.currentbiology.
com/cgi/content/full/14/1
2/R463/DC1/
References
1. Higuchi, R., von Beroldingen, C.H.,
Sensabaugh, G.F., and Erlich, H.A.
(1988). DNA typing from single
hairs. Nature 332, 543–545.
2. Allen, M., Engström, A.-S., Meyer,
S., Handt, O., Saldeen, T., von
Haeseler, A., Pääbo, S., and
Gyllensten, U. (1998). Mitochondrial
DNA sequencing of shed hairs and
saliva on robbery caps: Sensitivity
and matching probabilities. J.
Forensic Sci. 43, 453–464.
3. Forslind, B., and Swanbeck, G.
(1966). Keratin formation in the hair
follicle. Exp. Cell Res. 43, 191–209.
4. Baker, L.E., McCormick, W.F., and
Matteson, K.J. (2001). A silicabased
mitochondrial DNA
extraction method applied to
forensic hair shafts and teeth. J.
Forensic Sci. 46, 126–130.
5. Baker, L.E. (2001). Mitochondrial
DNA haplotype and sequence
analysis of historic Choctaw and
Menominee hair shaft samples.
(PhD Thesis. University of
Tennessee, Knoxville).
6. Bonnichsen, R., Hodges, L., Ream,
W., Field, K., Kirner, D.L., Selsor,
K., and Taylor, R.E. (2001).
Methods for the study of ancient
hair: Radiocarbon dates and gene
sequences from individual hairs. J.
Archeol. Sci. 28, 775–785.
7. Lindahl, T. (1993). Instability and
decay of the primary structure of
DNA. Nature 362, 709–715.
8. Hofreiter, M., Serre, D., Poinar,
H.N., Kuch, M., and Pääbo, S.
(2001). Ancient DNA. Nat. Rev.
Genet. 2, 353–358.
9. Wilson, M.R., Polanskey, D., Butler,
J., DiZinno, J.A., Replogle, J., and
Budowle, B. (1995). Extraction,
PCR amplification and sequencing
of mitochondrial DNA from human
hair shafts. Biotechniques 18,
662–669.
10. O’Connell, T.C., and Hedges,
R.E.M. (1999). Isotopic composition
of hair and bone: Archaeological
analyses. J. Archaeol. Sci. 26,
661–665.
11. O’Connell, T.C., and Hedges,
R.E.M. (1999). Investigations into
the effect of diet on modern human
hair isotopic values. Am. J. Phys.
Anthropol. 108, 409–425.
12. Wilson, A.S., Dixon, R.A., Dodson,
H.I., Janaway, R.C., Pollard, A.M.,
Stern, B., and Tobin, D.J. (2001).
Yesterday’s hair – human hair in
archaeology. Biologist 48, 213–217.
13. Yoshii, T., Tamura, K., and
Ishiyama, I. (1992). Presence of
PCR-inhibitors in hairs. Nippon
Hoigaku Zasshi 46, 313–316.
14. Endicott, P., Gilbert, M.T.P.,
Stringer, C., Lalueza-Fox, C.,
Willerslev, E., Hansen, A.J., and
Cooper, A. (2003). The genetic
origins of the Andaman islanders.
Am. J. Hum. Genet. 72, 178–184.
15. Gilbert, M.T.P., Hansen, A.J.,
Willerslev, E., Rudbeck, L., Barnes,
I., Lynnerup, N., and Cooper, A.
(2003). Characterisation of genetic
miscoding lesions caused by post
mortem damage. Am. J. Hum.
Genet. 72, 48–61.
16. Richards, M.P., and Hedges,
R.E.M. (2003). Bone collagen δ13C
and δ15N values of fauna from
Northwest Europe reflect
palaeoclimatic variation over the
last 40,000 years. Palaeogeogr.
Palaeoclimatol. Palaeoecol. 193,
261–267.
1Henry Wellcome Ancient Biomolecules
Centre, Department of Zoology,
University of Oxford, South Parks Rd,
Oxford OX1 3PS, UK. 2Current address:
Ecology and Evolutionary Biology,
University of Arizona,1041 E Lowell St.,
Tucson, Arizona 85721, USA.
3Department of Archaeological
Sciences, University of Bradford,
Bradford, West Yorkshire BD7 1DP, UK.
4Department of Biomedical Sciences,
University of Bradford, Bradford, West
Yorkshire BD7 1DP, UK. 5Department of
Evolutionary Biology, Zoological
Institute, University of Copenhagen, 15
Universitetsparken, Copenhagen Ø, DK-
2100, Denmark. 6Research Laboratory
for Archaeology, University of Oxford, 6
Keble Road, Oxford OX1 3QJ, UK. 7Max
Plank Institute for Evolutionary
Anthropology, Deutscher Platz 6, D-
04103, Leipzig, Germany. *E-mail:
[e-mail]
Current Biology Vol 14 No 12
R464
Table 1: Details of ancient hair samples analysed.
Sample* Species Details† Age‡ DNA§ Damage Templatesß Source
Tg415 Homo sapiens Onge 50ßß HVR1 0.0011 n/a Lehrmann
Tg468 H. sapiens Newton? 361-276** No n/a n/a Woolsthorpe Manor
Tg469 H. sapiens Newton? 361-276** HVR1 0.0007 7,200 Cullum Collection
Tg471 H. sapiens Newton? 361-276** No n/a n/a Royal Society
Tg472 H. sapiens Newton? 361-276** HVR1 0.0019 5,700 Lord Portsmouth§§
Tg473 H. sapiens Newton? 361-276** HVR1 0.0015 116,100 Lord Portsmouth§§§
Tg474 H. sapiens Newton? 361-276** HVR1 0.0011 n/a American Philosophical Society
Tg491 Bos bison Dominion Creek >64,500 CRS 0.0014†† 75,600 Christie Mine, Dawson, YT
16S 0.0050‡‡
Pazyryk 1 Equus caballus Ak-Alakha3 2800-2200 16S 0.0033 829,700 Molodin and Polos'mak
Pazyryk 4 E. caballus Verkh Kaljin II 2800-2200 16S 0.0033 1,219,000
Pazyryk 7 E. caballus Ak-Alakha3 2800-2200 16S 0.003 2,141,500
Pazyryk 8 E. caballus Ak-Alakha3 2800-2200 16S 0.001 n/a
*Sample: DNA extraction number. †Details: Original name of sample. ‡Age: Sample age in years. §DNA: Presence of amplifiable mitochondrial
DNA in extract, either HVR1, 16S, or control region sequence (CRS). Where not indicated, HVR1 was not amplifiable. Damage: Damage measured
as independent number of miscoding lesions per total bases of sequence amplified (excluding primer) [15]. If multiple extractions and
amplifications have been performed, the average observed damage is given. ßTemplates: Approximate amount of amplifiable DNA fragments
extracted from each 2 cm length of hair shaft analysed, as determined using Quantitative Real-Time PCR on serial dilutions of the 100 μl hair
shaft DNA extracts (where analysed). ßß Years since sampled. **Age assuming hairs are authentically from Sir Isaac Newton. The bison hairs
were sampled at Christie Mine, near Dawson, Yukon Territory, Canada. Bison CRS and 16S DNA sequences were independently replicated at
two institutions, ABC Oxford and University of Copenhagen. The 16S mtDNA sequence matched that amplified from a bison bone previously
extracted (BS200, M.T.P. Gilbert, unpublished data) and differed from Bos taurus at four sites. The control region sequence differed from B.
taurus, and grouped phylogenetically within a large dataset of ancient bison sequences. Isotopic data are consistent with the identification of
the sample as a bison (δ13C = -21.9 ‰, δ15N = 4.3 ‰), and is similar to modern and ancient herbivores [16]. §§ Hair attributed to Sir Isaac
Newton as a youth. §§§ Hair attributed to Isaac Newton as an old man. For full details on all samples and sequences see Supplemental Data.