Which DNA Do I Use? How to Choose Your Control and Other DNA Samples

 

DNA double helix molecules and chromosomes.

Today’s Promega Connections blog is written by guest blogger Joliene Lindholm, Promega Technical Services Scientist.

In Promega Technical Services, we are frequently asked questions about choosing among our Human Genomic DNA products. Promega offers DNA that can serve as sources of normal human gene sequences or positive controls where genotype is not critical, and controls for use in genotyping applications like STR analysis. For mouse researchers, we also offer Mouse Genomic DNA. Continue reading “Which DNA Do I Use? How to Choose Your Control and Other DNA Samples”

Rapid DNA Technology: Establishing your Identity in Less than Two Hours

DNA SequenceWhile the forensic and general communities continue to argue about the merits of the recent Supreme Court ruling on collection of samples from arrestees prior to conviction, I am fascinated by the technology that make this question relevant. The conventional way of generating a DNA profile from a sample by STR (short tandem repeat) analysis is a long process involving a series of steps that require sophisticated expensive equipment, trained personnel and, more importantly, time. The actual process of DNA analysis consists of a) sample collection, b) DNA extraction, c) PCR amplification using 16 or more unique fluorescently labeled primer sets d) capillary electrophoresis to size labeled DNA amplicons, e) software analysis to size DNA fragments and allele calls based on migration of allelic ladder fragments, and f) comparison to known profiles in the database. This entire workflow can typically take days or even weeks, and therefore it is not surprising that we see newspaper reports of backlogs of criminal and other property cases. With these time ranges, the sample collected at a site would be of no practical use to most ongoing investigations. Continue reading “Rapid DNA Technology: Establishing your Identity in Less than Two Hours”

Dietary Analysis, DNA Style

dna testing of foodDNA testing methods are being used to solve problems in an ever-increasing number of fields. From crime scene analysis to tissue typing, from mammoths to Neanderthals, and from Thutmose I to Richard III, both modern mysteries and age-old secrets are being revealed. The availability of fast, accurate, and convenient DNA amplification and sequencing methods has made DNA analysis a viable option for many types of investigation. Now it is even being applied to solve such mundane mysteries as the precise ingredients used in a sausage recipe, and to answer that most difficult of questions “what exactly is in a doner kebab?” Continue reading “Dietary Analysis, DNA Style”

King Richard III Identified

Richard IIIBy now, you’ve seen the headlines. The bones that scientists found buried under a car park in Leicester, England, have been identified as those of the last Plantagenet king of England: Richard III. For those of you who might be new to this story, archaeologists identified and excavated the most likely burial spot for Richard III, under a car park near the Leicester City Council building, and unearthed a human skeleton with skeletal abnormalities similar to those of Richard III. Geneticists were called in to perform DNA analysis to determine if these bones were those of the English king. The DNA findings were just recently released. Now that scientists can say beyond a reasonable doubt that these bones belong to Richard III, we are learning new things about the ancient king. Continue reading “King Richard III Identified”

Toilet Paper: The Newest Tool in the Fight Against Crime

A roll of toilet paperIn July of 2009, the bodies of 43-year-old Alan Grna and his 85-year-old mother Julianna were discovered in their Ohio home—both victims of a violent assault. The lead detective in the case called in the Ohio Bureau of Criminal Identification and Investigation (BCI) to collect evidence from the crime scene, evidence that would lead them to the man who was eventually convicted of their murders. One of the key pieces of evidence was a roll of toilet paper.
Continue reading “Toilet Paper: The Newest Tool in the Fight Against Crime”