In a general sense the term pcr signifies repeated

This preview shows page 113 - 115 out of 542 pages.

We have textbook solutions for you!
The document you are viewing contains questions related to this textbook.
Biology: The Unity and Diversity of Life
The document you are viewing contains questions related to this textbook.
Chapter 13 / Exercise 9
Biology: The Unity and Diversity of Life
Starr/Taggart
Expert Verified
In a general sense, the term PCR signifies repeated replication of a segment of sample DNA by using suitable primer(s) and DNA poly- merase. In this sense, all applications of the tech- nique would qualify as PCR. But in a restricted sense, the term PCR signifies amplification of a specific sequence from the sample DNA; this PCR procedure differs in many ways from the other applications of the technique. The various features of PCR (in the restricted sense) and RAPDs are summarized in Table 3.3 . Table 3.3 A comparison between PCR and RAPD procedures Feature PCR RAPD Amplified region Specified/known Random Prior sequence information of the target segment Essential for designing the specific primers Not required; primer sequence is arbitrary Primer sequence Complementary to the 3 0 ends of the two strands of the target DNA segment Arbitrary; specified by the experimenter Number of primers Two: one forward and one reverse One Primer length 15–22 nucleotides 10 nucleotides Primer binding sites Fixed (due to the primer sequence); usually, one Random; usually, more than one Annealing temperature High (around 65 ± C; ~1–2 ± C less than the T m of the primer a ) Low (around 36 ± C; ~5 ± C less than the T m of the primer a ) Annealing conditions High stringency Low stringency Number of amplified fragments/bands One (usually) or few Several Reproducibility High Moderate to poor a T m of the primer is the melting temperature of the primer–template duplex. T m of a DNA duplex can be estimated from the following formula T m ¼ 4 G þ C ð Þ þ 2 A þ T ð Þ where G + C and A + T represent the numbers of purine (G + C) and pyrimidine (A + T) residues in one strand of the DNA duplex Appendices 75
We have textbook solutions for you!
The document you are viewing contains questions related to this textbook.
Biology: The Unity and Diversity of Life
The document you are viewing contains questions related to this textbook.
Chapter 13 / Exercise 9
Biology: The Unity and Diversity of Life
Starr/Taggart
Expert Verified
Sequence-Based Markers 4 4.1 Introduction The DNA markers like RFLPs, AFLPs, and SSRs were extensively used in various biological investigations and for marker-assisted selection (MAS) in both animals and plants. However, the development of many of these markers, e.g., RFLPs and SSRs, is demanding and expensive as it involves time-consuming cloning, construc- tion of probe libraries, and/or sequencing for primer design. In addition, scoring of a number of these markers across many individuals is also expensive, labor intensive, and time-consuming. Therefore, continuous efforts were made to develop such DNA markers that are reliable, abundant, almost evenly distributed throughout the genome, and relatively cheaper, developed with minimum effort and time and are amenable to automation and high-throughput genotyping. The genome sequence data generated by the human genome-sequencing project revealed that bulk of sequence variation among different individuals was due to changes at single-base positions distributed throughout the genome. The variation in single base pairs of DNA is known as single nucleotide polymorphism ( SNP ). Subsequently, SNPs were found to be universal and the most abundant markers; they constitute ~90 % of the genetic variation in any organism. This marker system yields reliable and reproducible results and is amenable to automa- tion

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture