Random Amplification of Polymorphic DNA (RAPD)
Random amplified polymorphic DNA (RAPD) markers are analyzed by using PCR to amplify the segments of nuclear DNA. The use of a single primer (usually 8–10 bp long) that attaches to both strands of DNA and low annealing temperatures increases the likeli¬hood of amplifying multiple regions representing a particular locus (Welsh and McClelland, 1990). Although RAPD is a simple and inexpensive technique its major limitation is the inability to differentiate between homozygote and heterozygote; this marker is therefore regarded as a dominant type. This technique is based on the use of short, arbitrary primers in PCR reaction and can be used to produce relatively detailed and complex DNA profiles
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Presumably primer sites are randomly distributed along the target genome, and flank both conserved and highly variable regions. Wide variation in band intensity can be shown to be reproducible between experiments, which could be the result of multiple copies of the amplified regions in the template or the efficiency with which particular regions are amplified (Bardakci, 2001). The polymorphic bands obtained from a RAPD can also be cloned for further analysis. The major advantage of RAPD includes that, it does not require pre-sequencing of DNA (Nandani and Thakur, 2014). RAPD-PCR fingerprints have been successfully used in defining genetic diversity among different species (Lynch and Milligan, 1994). For example, the RAPD method was used to generate specific fingerprint patterns of ten different species: including wild boar, pig, horse, buffalo, beef, venison, dog, cat, rabbit, and kangaroo (Koh et al., 1996). RAPD markers have several obvious features as summarized here as:
1) no prior sequence knowledge is necessary for designing the specific primers, which can then be used in different templates (Weising et al., 2005).
2) The amount of DNA required is very small because it will be amplified by PCR.
3) RAPDs are simple, quick, and cost effective compared to RFLP (Koller et al., 1993).
Parejo et al., (2002) suggested that RAPD is an important aid in planning the most adequate mating strategy to maintain the genetic diversity and to
20 ul of DNA was added to 20ul of Master Mix. The Master Mix contained primers, dNTPs, Mg2+, Taq DNA polymerase, and yellow dye. Both the DNA and Master Mix were mixed with the micropipette. The DNA was then put into the thermal cycler containing 40 cycles of PCR amplification, amounting to 3.5 hours of amplification.
(PCR), which isolates small fragments of DNA that have a high degree of variability from
Just like with the species specific primers, if you use a mammal primer and the DNA does not amplify then your DNA sample is not from a
Inbreeding is the outcome of offspring from mating of individuals that are related by a descent. It is important to limit this effect in conservation programs due to the increased amount of homozygosity and exposed deleterious recessive alleles, which increase the risk of extinction to the population.
Experiment 6: The DNA concentration after TAS2R38 PCR purification and quantification was 0.344 ng/µL (34.4 ng/mL). My genotype at the TAS2R38 locus was not determined by the sequencing. The genotypic frequencies of the class obtained by sequencing: 0.4 (40%) TT, 0.4 (40%) Tt, 0.2 (20%) tt. The allelic frequencies of the class obtained by sequencing: 0.6 (60%) T and 0.4 (40%)
Biological Background: It is scientifically proven that DNA (deoxyribonucleic acid) contains genetic material and highly specific to individual. DNA fingerprint can be tested by restriction fragment length polymorphism (RFLP) methods and Polymerase chain reaction (PCR) methods. Although RFLP is considered more accurate, due to the cost and requirement of longer period to complete, it is not commonly used. While only 1% of genetic materials are unique to individual, the short tandem repeats (STR) sequences called minisatellites can be used to distinguish all humans as it shows great variation between each person (What is DNA fingerprint? 2016).
The following results were used in order to identify what haplogroup my maternal lineage is apart of. In Figure 1 lane 6 shows my 5 uL mixture of DNA and 6X loading dye in well, this helped determine if the reaction work and the size. Then Nandrop 2000 was used in order quantify the DNA to determine the concentration. The concentration determined was 39.3 ng/ul and the ratios calculated were A260/280 1.68, A260/230 0.58. The ratio of the absorbance at 260nm and 280nm was used to determine the purity of DNA found in the PCR product by looking at nucleic acid and protein extraction. In general, a ratio roughly around 1.8 qualifies as a pure DNA sample so in this case my DNA was slightly pure. The ratio of absorbance at 260nm and 230nm is a secondary measure of nucleic acid purity.
The initial step of Sanger sequencing, designing primer pairs for PCR, is often performed manually, with the aid of software such as Primer-Blast that can analyse only one genetic locus at a time, or PCR Suite, that can analyse more than one locus, but does not check for specificity. The manual design of primer pairs is especially cumbersome and prone to errors for long lists of genetic loci.
DNA profiling is a method of identifying an individual by unique characteristics of their DNA. A specific DNA pattern, called a profile, is obtained from an individual or a sample of tissue. This allows the comparison of the base sequence of two or more DNA samples to determine whether they are related.
The polymerase chain reaction or PCR for short can be used to create many copies of DNA. This allows the DNA to then be visualized using a dye like ethidium bromide after gel electrophoresis. The process has been refined over the years, however the basic steps are similar.
Reference primers (PowerUp SYBR Green Fast PCR master mix, forward primer, reverse primer and ultrapure water).
The advantages of DNA based markers are that they are selectively neutral, abundant and have a wide coverage in the genome of all species. DNA based markers have been widely used in genetic studies of various crop plants that include cat’s whiskers (Kafesu, 2012) and tobacco (Mwadzingeni et al., 2013). Several DNA-based techniques can be used for characterization and these include simple sequence repeats (SSR), amplified fragment length polymorphism (AFLP), restriction fragment length polymorphism (RFLP) and randomly amplified polymorphic DNA (RAPD) (Villa et al., 2005). These techniques are all fairly effective. Their choice depends on the stage of research into
The process of DNA fingerprinting in humans involves the replication and arrangement of extracted DNA, to create a pattern/fingerprint that is viable for comparison. This process involves the application of DNA extraction, digestion by restriction enzymes, Polymerase Chain Reaction (PCR) and gel electrophoresis. This results in a DNA profile with bands of varying widths that can be used for the comparison of genetic information. DNA extraction occurs in three stages. Firstly, a
SCAR markers are PCR based primers that represent genomic DNA fragments at genetically defined loci, that are identified by PCR amplification using sequence specific oligonuceotide primers (Paran and Michelmore, 1993; Me Dermott et al., 1994). Inception of SCARs involves cloning the amplified products of arbitrary marker techniques and then sequencing the 2 ends of the cloned products. The sequence s therefore used to design specific primer pairs of 15-30 bp which will amplify single major bands of the size similar to that of the cloned fragment.
The knowledge of genetic variability is a pre requisite to study the evolutionary history of a species, as well as for other intraspecific variation, genetic resource conservation etc. (Islam et al. 2007). Hence, genetic diversity and gene differentiation through molecular marker analysis are essential for their taxonomic relationship evaluation, conservation and sustainable utilization. For proper conservation programme it is essential to characterize the plants genetically. Number of molecular markers is being regularly used for studying genetic relations, population genetics, genetic characterizations in different plant groups and cultivars. The molecular markers are not influenced by the external environmental factor unlike that of morphological markers and hence accurately testify the genetic relationship between and among plant groups. Molecular markers like RAPD, ISSR and SSR are being used regularly for genetic diversity assessment as a thorough knowledge of the level and distribution of genetic variation is essential for conservation (Dreisigacker et al. 2005; Sharma et al. 2008; Naik et al. 2010; Das et al. 2011). PCR-based DNA fingerprinting techniques like RAPD, ISSR and SSR are proven to be very informative and cost-effective