Bacteria next crime Fighting tool

Scientists think bacteria may be the next crime-fighting tool.
Forget fingerprints: The latest crime fighting tool may be the traces of bacteria we carry on our skin. A new study shows it is possible to identify people based on their personal brand of bacteria. "Each one of us leaves a unique trail of bugs behind," a researcher says. By tracing that trail, scientists were able to match samples to specific people with 70% to 90% accuracy. "We think the technique could eventually become a valuable new item in the toolbox of forensic scientists,” he tells the Independent.

The process is unlikely to replace fingerprinting—which can find a perfect match—but would be used when fingerprints aren't available. To make the breakthrough, researchers relied on a relatively new approach called “metagenomics,” which allows scientists to analyze an entire collection of genomes in one go.

Software That Exposes Faked Photos

Using algorithms designed to sniff out suspicious shadows, computer scientists from Dartmouth and the University of California, Berkeley, say they have developed software that can reliably detect fake or altered photos.

The technique could be useful in the emerging field of photo forensics, said Hany Farid, a Dartmouth computer science professor and developer of the software. In the age of Photoshop, detecting manipulated photos is a growing priority for lawyers, journalists and people involved in law enforcement and national security.

To determine an image’s authenticity, the software uses geometric formulas to analyze shadows to determine if they are all physically consistent with a light source. Inconsistencies with the light or within the shadows themselves —some of which may be invisible to the naked eye .

Demands for paternity testing have increased reflecting the instability of family relationship and infidelity issues occur more . Lets know about DNA and how does paternity testing done ?how accurate is DNA paternity testing ?

Deoxyribonucleic acid (DNA) is a molecule that encodes the genetic instructions used in the development and functioning of all known living organisms and many viruses. DNA is a nucleic acid; alongside proteins and carbohydrates, nucleic acids compose the three major macromolecules essential for all known forms of life. Most DNA molecules are double-stranded helices, consisting of two long biopolymers made of simpler units called nucleotides—each nucleotide is

composed of a nucleobase (guanine, adenine,thymine, and cytosine), recorded using the letters G, A, T, and C, as well as a backbone made of alternating sugars (deoxyribose) and phosphate groups (related to phosphoric acid), with the nucleobases (G, A, T, C) attached to the sugars. DNA is well-suited for biological information storage. The DNA backbone is resistant to cleavage, and both strands of the double-stranded structure store the same biological information. Biological information is replicated as the two strands are separated. A significant portion of DNA (more than 98% for humans) is non-coding, meaning that these sections do not serve a function of encoding proteins.

For paternity testing Any  kind of biological sample: blood, saliva, hairs, semen, amniotic liquid, biopsy, skeletal remains, nails, cigarette butt, chewing gum, envelopes, toothbrush or other organic remains present in all kind of clothes or objects. All cells of a person have the same DNA, so the accuracy and reliability of the results are the same, independent of the biologic material used.

HOW ACCURATE IS DNA PATERNITY TESTING?

DNA testing is the most accurate paternity and family relationship testing method currently available. Every person has a unique DNA fingerprint except for identical twins. We all inherit half of our DNA from our biological father and half from our biological mother. DNA testing tries to discover the 50% match between the child’s and the parent’s DNA profiles to prove or disprove the blood relationship. DNA parentage testing is considered to be 9you can take a paternity test before the child is born. Universal Genetics offers prenatal DNA paternity testing service to those who wish to find out paternity during pregnancy. An OB-GYN is involved in collecting the baby’s specimen during a period of time that presents the least risks to the fetus and the mother. The testing results are as accurate as a standard paternity test conducted after the child is born.99.9% accurate.

How do DNA samples for paternity testing become contaminated?

Swabs may become contaminated by contact with anther person’s DNA, maybe by someone who is collecting the sample. This can happen by someone inadvertently handling the tips of the swab, or dropping the swab. According to Dr. Donna Housley, the IDENTIGENE  lab director, “Sometimes the swabs are contaminated because people mix up the envelopes and put swabs from 2 different people in the same envelope, this is quite common. Also if a person has ever had a bone marrow transplant or a recent blood transfusion the profile could come back contaminated because we see two profiles from one individual when we amplify the DNA.”

When submitting DNA samples for paternity testing, avoid the original plastic packaging.

DNA Collection

Something else you want to avoid is placing the DNA collection swabs back into the plastic wrapper it originally arrived in. You want to place the samples directly into the paper envelope provided in the IDENTIGENE DNA collection kit.

Blood as a evidence its collections and precautions

we  have seen ,mostly after crime scene, investigator and  experts  team arrived  there  and  searching for clues and collecting samples and take notes and  photographs,but during that time the chances of  contamination increases to avoid this error  collection and proper precautions rules must be followed .

Any  kind of Contamination of  bodily fluids like Blood,semen,saliva,sweat  may destroy the importance and  they will not give accurate  result after scrutinisation.Because of mixup foreign matter or due to human error ,and lots of external factors affects  the  biological evidence   which alters there identity ,bodily fluids are differ from one individual to other so if sample is contaminated or any other sample  are introduces due to human error or while lifting or during packing of samples. The following are guidelines, listed in order of the author’s preferences, for collecting and preserving blood evidence:

Most items of evidence will be collected in clean, unused paper containers such as packets,envelopes, and bags. Moist or wet biological evidence (blood, body flu ids, plants, etc.) from a crime scene can be collected in clean, unused plastic containers at the scene and transported back to an evidence receiving area if the storage time in sealed plastic is less than two hours and this is done to prevent contamination of other evidence. Once in a secure location, wet evidence, whether packaged in plastic or paper, must be removed and allowed to completely air dry. That evidence can then be repackaged in a new, clean, unused, dry paper container. UNDER NO CIRCUMSTANCES SHOULD EVIDENCE CONTAINING MOISTURE BE SEALED IN PLASTIC OR PAPER CONTAINERS FOR MORE THAN TWO HOURS. Moisture allows the growth of microorganisms that can destroy or alter evidence.

Any items that may cross contaminate each other must be packaged separately. The containers should be closed and secured to prevent the mixture of evidence during transportation. Each container should have the collecting person’s initials: the date and time it was collected; a complete description of the evidence and where it was found; and the investigating agency’s name and file number.

Before transporting any items of evidence, the investigator should examine the items to determine if there is any loose trace evidence (hairs, fibers, paint chips, etc.) that may be lost in transportation. If there is, then this loose evidence should be collected in a paper packet and placed in an envelope. The envelope should have the required information giving a description and the source of the trace evidence. The actual item can then be processed and collected.

Blood evidence must never be exposed to excessive heat or humidity. If possible, the bloodstained evidence should be refrigerated until it can be transported to the crime lab. The evidence should also be taken to the lab as soon as possible.

Dried BloodstainsDried Bloodstains

If the bloodstained item is small and transportable, package it in a paper bag or envelope.
Advantages: Requires a minimal amount of interaction with the bloodstains by the investigator: allows the serologist to make the decisions involved in collecting the samples; dilution and contamination potential minimized by eliminating the use of water as the collection medium.
Disadvantages: More work for the serologist: bulky items require more storage space.

If the bloodstained item is large or not easily transported, then the following techniques can be used for collecting the bloodstains. If possible, the investigator should also collect samples from unstained areas of the item for negative controls.

Cutting out the portion(s) of item with the bloodstain(s). A negative control area should also be cut out if available. Package cuttings in separate paper envelopes.
Advantages: Dilution and contamination potential minimized by eliminating the use of water as the collection medium: requires only a small amount of investigator interaction with the bloodstain: does not usually take up much storage space.

Wet Bloodstains

If the item is small and transportable, then package it in a paper bag (or plastic bag to prevent contamination of other objects). Bring it to a secured location, take it out of the bag and allow the evidence and the bag to thoroughly air dry. Repackage in the original paper bag or, if necessary, a new paper bag. If a new paper bag is used, then the air dried original container should be packaged with the item of evidence.
Advantages: Requires a minimal amount of interaction with the bloodstains by the investigator; allows the serologist to make the decisions involved in collecting the samples.

DNA Fingerprints and contaminations ..

1. Place the item in numerical order within the bins in the refrigerator and freezer by case number.

1. When DNA typing was a new technology, its introduction to the courts in the U.S. was hotly contested by some scientists. One objection was that the DNA typing process itself was not meeting ideal data criteria. Initially, there were NO rules for DNA labs, and there were no certification procedures.  Databases for evaluating RMPs were inadequate.  Many of the former problems have been resolved with database expansion and with technologies that removes the subjectivity in assigning DNA type to a sample, but problems still remain, at least for some labs.  In summer of 2003, the Houston Crime Lab made the news by having such sloppy DNA procedures that even the local authorities recommended withdrawal of its certification.  Dr. Larry Mueller’s web page at U.C. Irvine (http://darwin.bio.uci.edu/~mueller/ go to “Forensic DNA Resources” at the bottom of the left menu) lists some of the lab errors that he has encountered in his experiences as an expert witness for the defense.  Another, more recent and comprehensive site is http://www.scientific.org/.  Since most or all of these errors favored the prosecutions’ cases until they were discovered, there is no incentive for the government to maintain a public record of them.
2. The types of errors and problems most commonly encountered fall into a few types (A and D are apparently the most prevalent):
3. A)   sample mixup.  This is probably the most common source of false matches – the people in the lab mixed up the samples.  Sample mixup is understandable simply because the technologies involve use of standardized tubes and other plasticware, and unless one is absolutely rigorous, it is very easy to accidentally grab the wrong tube, or load the wrong well with a sample.  Ultimately, every sample is handled by a person before it gets processed, and this step of human handling is the vulnerable one.
4. B)   Sample contamination.  Some cases of sample contamination are similar to sample mixup.  In other cases, sample contamination occurs because an officer touches the material with his/her hands, or the contamination may occur when the sample is deposited (e.g., if a blood stain gets bacteria in it).
5. C)   DNA degradation.  DNA degrades if it is not kept cold or dry.  Thus, by the time the police arrive at a crime scene, the DNA in some of the samples may already be bad.  Improper storage of samples also contributes to degradation.  Degradation may lead to inaccurate DNA typing, though more so for the STR method than for the mitochondrial method.
6. D)   Bad data analysis.  The calculation of RMP may be straightforward in many cases, and some software automatically calculates it for each STR.  However, unusual cases require a deep understanding of probabilities (and statistics), which if often lacking.