Correcting for Errors Inherent in DNA Pooling Methods
Professor’s comment: This student’s research paper describes developments and refinements in an effort to correct for errors inherent in the DNA pooling methods employed in genetics research. I admire the clarity and efficiency with which she explains these developments.
Introduction
Many genetic diseases have yet to be located on the human genome for reasons that include their multiple loci and incomplete penetrance. To pinpoint these loci in terms of particular regions of the chromosomes, association studies, which compare allele frequency between affected individuals (probands) and controls, must be performed across the entire human genome. With approximately 0.4 cMs between markers, 10,000 microsatellite markers would be necessary to fully saturate the genome (Collins et al., 2000). For a study of 1000 probands and 1000 controls, 20 million genotypings would be required (Collins et al., 2000). Because of the relative impossibility of such a task, a technique called DNA pooling has been developed. DNA pooling involves the mixing of equal amounts of DNA from each individual in a group and then proceeding as one would with individual samples—by performing a PCR and running the samples out on a gel. DNA pooling can determine total allele content of a group, for one microsatellite, without the need to individually genotype each individual in that group. As such, it is an effective way to decrease the number of genotypings required, reducing the workload by factors of tens or hundreds.
Although the benefits of DNA pooling are immense, two significant sources of error must be addressed. The first, known as stutter peaks, results from a slippage of the DNA polymerase during the PCR replication process. Stutter peaks appear as progressively smaller peaks before each real allele peak and result in artificially inflated values for the smaller allele sizes. This error is consistent and reproducible for a particular marker (Perlin et al., 1995). The other major source of error is caused by preferential amplification of some alleles over others. In this situation, uneven PCR replication and amplification result from the differing sizes of the fragments being replicated. Over the years, several methods have been developed to overcome these sources of error, making DNA pooling a practical method of screening for disease loci.
Early Methods for Stutter Correction
LeDuc et al. (1995) developed one of the first methods to correct for the stutter artifact by measuring the allele and stutter peak heights for the smallest allele of the pool and any allele not immediately adjacent to other alleles.
revealed that three of the fourteen samples were were homozygous while the other eleven were
Bram Stoker’s Dracula includes themes of death, love, and sex. Stoker’s use of empiricism utilizes the idea that everything is happening “now”. The book offers clear insight into who is evil without explicitly saying it. Stoker’s interest in empiricism uses British womanhood as a way to distinguish between good and evil.
In the 19th century Bram Stoker wrote the infamous novel, Dracula. This novel was composed in the style of letters, journal entries, newspaper articles and telegrams in order to convey to the reader a realistic story. The story of Dracula is about an ancient vampire who moves to London from his native country of Transylvania. In London, Dracula seduces and bites a young woman by the name of Lucy Westenra. When Lucy falls sick, no one knows how to help her because while Dracula has bitten her many times she has always been in a trance. Lucy?s friends decide to join together to combat what ever is ailing Lucy. In hopes of some help, Lucy?s friend Dr. Seward asks an old mentor of his by the name of Dr. Van Helsing to come to London and solve this puzzling illness. When Dr. Van Helsing arrives in London and sees Lucy he is the only one that knows almost immediately what has happened and what they are up against. The character of Dracula rarely appears in the story because this creates suspense and magnifies the fear of the unknown. The theme of good versus evil is developed throughout the book in many ways. One of the most important examples is Dracula and Mina. Dracula is the ultimate evil and Mina is full of goodness and purity. The Victorian view of women was not helpful to the characters in Dracula. For example, every time the male characters in the story decide not to tell Mina some particular type of information, things end up going terribly wrong. Even though Mina ends up being the key to destroying Dracula she is still a women and the Victorian view gets in the way.
On the surface, Dracula is a story of the battle of good and evil, however it has many other attributes. Christian Redemption, science and technology, and sexual expression, among many others, are ideas that Stoker explores in his book. The themes that Stoker chooses to portray are representative of the Victorian Era ideals. The many themes that are present in Dracula are brilliantly entangled within the plot.
Stoker, Bram. Dracula: Complete, Authoritative Text with Biographical, Historical, and Cultural Contexts, Critical History, and Essays from Contemporary Critical Perspectives. Bedford St. Martins, 2002. Print.
Stoker’s Dracula is aristocratic, well mannered, and highly educated with “humanistic touches [which] make Dracula appear noble and vulnerable” (Senf 424). Initially, Dracula seems like a modern man, hospitable, and capable of aging. Dracula is a middle aged man with “astonishing vitality” for his presumed age. He also has impeccable manners, caring for his “guest” when his “people are not available” (Stoker 22-3). Dracula is an educated man, as suggested through his library with books “of the most varied kind – history, geography, politics, political economy, botany, geology, law – all relating to England and English life and customs and manners” (25). He seems not only well informed but cosmopolitan, asking Harker “a myriad questions” (28). Harker observes “extraordinary evidences of wealth” (25) alluding to Dracula’s position as a wealthy “boyar” (26). These evidences cause Jonathan Harker to presume Dracula possesses conventional moral principles. Harker, being disarmed by his presumption, causes him to believe he is safe with Dracula. However, Harke...
Prescott, Charles E., and Grace A. Giorgio. “Vampiric Affinities: Mina Harker and the paradox of Femininity in Bram Stoker’s Dracula.” Victorian Literature and Culture 33 (2009): 487-515. JSTOR. Web. 29 April 2013.
Abstract; This paper explors the effects DNA fingerprinting has had on the trial courts and legal institutions. Judge Joseph Harris states that it is the "single greatest advance in the search for truth since the advent of the cross examination (Gest, 1988)." And I tend to agree with Judge Joseph's assertion, but with the invention and implementation of DNA profiling and technology has come numerous problems. This paper will explore: how DNA evidence was introduced into the trial courts, the effects of DNA evidence on the jury system and the future of DNA evidence in the trial courts.
Throughout decades of cheesy horror movies, the image of vampires have been misconstrued as sparkly, angsty teenage boys or handsome men that lure in girls for the fresh blood of a virgin. Many of these stereotypical vampires are influenced by the story of Dracula, held in the Victorian era. During this period, sexuality is repressed by society, as sexual behaviors from women are viewed as unacceptable. Yet, many of the stories published about vampires diverge from the message that Bram Stoker was trying to make. In the Gothic horror novel Dracula, Bram Stoker uses the traumatic experience of Jonathan Harker at Count Dracula’s castle and the invasion of vampires in Great Britain to create a social commentary on the sexual repression occurring
Service learning is a rather new concept, but it has proven advantageous in connecting students with their communities when paired with reflection and when included in school curriculum. . Weigert’s (1998) view of ser...
The majority of scientific work in genetics and genomic sequencing has been done in the last 155 years. In 1859, Charles Darwin published On the Origin of Species where he proposed evolution by natural selection. Evolution is the change of inherited characteristics of biological populations over successive generations.Yet, the principals of genetics required to explain how characters are ...
By analyzing the frequency of crossovers for many different alleles can trace a linear map of each chromosome.
“Dracula, in one aspect, is a novel about the types of Victorian women and the representation of them in Victorian English society” (Humphrey). Through Mina, Lucy and the daughters of Dracula, Stoker symbolizes three different types of woman: the pure, the tempted and the impure. “Although Mina and Lucy possess similar qualities there is striking difference between the two” (Humphrey). Mina is the ideal 19th century Victorian woman; she is chaste, loyal and intelligent. On the other hand, Lucy’s ideal Victorian characteristics began to fade as she transformed from human to vampire and eventually those characteristics disappeared altogether. Lucy no longer embodied the Victorian woman and instead, “the swe...
...battle to life. In the novel, on the other hand, Stoker makes sure that his female character triumphs (by surviving) and that she returns home to “become a dutiful wife and caring mother”. This is where we could argue that “Stoker is much ahead of his times in portraying a ‘New Woman surpassing even the best male ‘professionals’ in terms of intellectual labor, a ‘gallant’ woman wit a remarkable ‘man-brain’ who helps save the empire, even though her power abruptly dimishes toward the end of the novel, and she is finally summoned home to become a traditional mother figure” (Kwan-Wai Yu 158). Although Stoker was very accurate in the new scientific and technological advances that he incorporated into Dracula, he was also very accurate in portraying a strong willful woman who is able to complete a job that was unwittingly given to her in the most extraordinarily manner.
Adultery is a horrible sin to commit, but it can actually be avoided, although many people in today's society respond differently based on their religion and culture. When a person commits adultery they fail in keeping his/her commitment to their partner. When adultery happens the trust is broken in the relationship and the other person will feel deceived and betrayed.