Dna Recombination In Genetic Engineering

Better Essays
Abstract DNA recombination is basically generation of the new DNA sequence in genome by exchange of DNA strands. Recombination generally but not necessarily occurs between similar DNA sequences and provides genetic variation, genome integrity [1]. There are four main ways being identified to produce recombinant DNA; homologous recombination in which physical exchange of DNA sequences occur between the homologous chromosomes, illegitimate recombination occurs between DNA sequences sharing low sequence similarity, site specific recombination require recombination enzymes that specifically bound short nucleotide sequence where cleave and rejoining occurs. The last class is transposition in which mobile DNA element move from one location to target …show more content…
Transposition shows little sequence selectivity unlike the homologous recombination for insertion but require specific enzymes to move the different locations within genome. Also, transposition (class I) is widely resulting in duplication of original DNA sequences. There are considerable diversity among transposition elements and mainly classified into two groups according to their movement mechanisms. Class I is retro-transposons which use a RNA intermediate in transposition mechanism and Class II is DNA transposons remaining as DNA throughout transposition [4]. Retro transposons first transcribe themselves in RNA and then RNA is copied to DNA again by reverse transcriptase which is generally encoded by mobile elements. Copied DNA is inserted into target site. The main class of retro transposons are virus like and poly A retro transposons. On the other hand, the distinctive property of Class II mechanisms which generally use cut and paste mechanism does not involve RNA intermediated in their transposition. The enzyme called transposase cut the target sequence and generates sticky ends. The transposon which is cut out is then ligated to acceptor sequence. There are also DNA transposons such as Tn3 and IS1 which copy themselves into target site rather than cut/paste and cause replication of donor …show more content…
cerevisiae and drosophila (Rothstein 1991; S. Rong 2002). Especially in yeast cells, HR is commonly used method for gene targeting due to high efficiency. Yeast cells can grow as haploid/diploid forms; it provides specific advantage to study lethality-gene relationship and yeast mating type switch stimulates the efficient homologous recombination machinery. Target gene can be disrupted by using plasmid containing nonfunctional copy of gene, selectable marker flanked by short ~40 nucleotides homologous to target gene [5]. Basically, nonfunctional copy of gene is cloned into plasmid vector containing selectable marker. Then vector transformed into yeast cells integrates target site in the genome by HR. The major advantage is that this methodology is systematically efficient enough to mutagenize annotated ~6200 yeast ORFs due to known sequence information. Nevertheless, frequency of HR could be increased by introducing double strand break (DSB) within the plasmid sequence having homology with target gene. DSB typically repaired by non-homologous end joining or HR which cause gene conversion. Orr-Weaver et al. signified that the position of double strand break is important factor and affect frequency of genetic exchange [6]. Afterwards, it was shown that recombination frequency is increasing when circular vector is linearized (Orr-Weaver,

Related Documents

  • Decent Essays

    One for instead was “Enhancer”. Enhancers change how active genes are. Enhancer relates to the article by having an enhancer close to a different type of genes it can show whether the genes are active or silenced. Closeness relates to the folding and looping of DNA.Another word is “Chromatin Modification” The alteration of DNA which can determine how tightly genes can be stored. In Chromatin Modification DNA is surrounded by proteins called “Histones”.…

    • 802 Words
    • 4 Pages
    Decent Essays
  • Decent Essays

    Dna Synthesis

    • 1283 Words
    • 6 Pages

    The nick or spaces between the new DNA strands are joined using the enzyme DNA ligase resulting in the formation of two long daughter strands of DNA (Campbell et al., 2015). After the two daughter strands of DNA have been produced, it is time to proofread and repair the DNA sequence. This process is so important because any mistake in DNA replication can result to DNA mutation and will lead to various genetic diseases such as sickle cell anaemia, Huntington’s disease and many more (Cooper, 2000). Thus, the accuracy of DNA replication cannot be attributed solely to the specificity of the base pairing. According to Khan Academy (2017), to avert the mistake from happening, an enzyme which is DNA polymerase will proofread each nucleotide against its template as soon as it is covalently bonded to the growing strand.…

    • 1283 Words
    • 6 Pages
    Decent Essays
  • Decent Essays

    As the DNA is unwound, this creates a replication fork. Since replication occurs in a bi-directional way, a leading and lagging strand are produced. The leading strand is made in the same direction as the replication fork, nucleotides are added continuously. The lagging strand is made in the opposite direction of the replication fork. This discontinuous synthesis of DNA causes short segments of DNA called Okazaki fragments to be formed.…

    • 1415 Words
    • 6 Pages
    Decent Essays
  • Decent Essays

    Eukaryotic Synthesis

    • 1359 Words
    • 6 Pages

    DNA produced mRNA in transcription in which the mRNA will be decoded to build a polypeptide chain of amino acids in translation. This process is one of the most complicated tasks that cells can perform using a great deal of energy to do so. To translate mRNA into a protein it requires a series of detailed steps and molecules including initiation, elongation and termination. After transcription is complete the mRNA leaves the nucleus and travels into the cytoplasm. Translation may occur in either the cytoplasm or the rough endoplasmic reticulum.…

    • 1359 Words
    • 6 Pages
    Decent Essays
  • Decent Essays

    By separating the strands a single one of them is then able to be replicated. When the strands are separated it creates a Y shape which is called a replication fork. A short primer from RNA is used as a starting point on one of the strands to replicate the DNA. A DNA polymerase enzyme, used to assemble nucleotides, binds its self to the leading strand adding new nucleotide bases to the strand. When the base are matched up the enzyme exonuclease removes the primers and the gaps are filled with more nucleotides.…

    • 1003 Words
    • 4 Pages
    Decent Essays
  • Decent Essays

    Protein mutations are often introduced at the DNA level in the corresponding gene, which takes advantage of the central dogma of biology (DNA is transcribed to mRNA; mRNA is translated to proteins. The introduction of mutations in target genes has become trivial with the advances in synthetic biology. Major classes of library construction include (1) random mutagenesis, (2) recombination, (3) semi-rational design, and (4) scanning mutagenesis. Together, these classes of library construction are termed “combinatorial design” and require little to no prior knowledge of the protein, albeit more knowledge can help design libraries more efficiently. The counter technique is termed “rational design” and requires detailed information about the…

    • 1120 Words
    • 5 Pages
    Decent Essays
  • Decent Essays

    Recombinant Dna Synthesis

    • 1949 Words
    • 8 Pages

    Recombinant DNA is genetically engineered DNA that is formed by splicing fragments of DNA. Organismal cloning is the artificial creation of a new organism that is genetically identical to its counterpart. DNA cloning is a recombinant DNA technique where cDNAs and fragments of genomic DNA are inserted into a cloning vector and maintained during growth of the host cells. Vector is an agent that transfers genetic material into a cell or organism. Restriction enzymes are bacterial enzymes that find restriction sites and cleaves DNA.…

    • 1949 Words
    • 8 Pages
    Decent Essays
  • Decent Essays

    Dna Synthesis Essay

    • 795 Words
    • 4 Pages

    These end goes in towards the replication fork while the DNA molecule unzips. The enzyme which is analyzing this is called DNA polymerase. The second strand of DNA is built by having polymerase go in and on the strand and fill in the nucleotides backwards. Now these strands will move outwards away from the replication fork. The DNA polymerase starts a burst of synthesis at the replication fork.…

    • 795 Words
    • 4 Pages
    Decent Essays
  • Decent Essays

    Genetic Engineering

    • 1334 Words
    • 6 Pages

    This process takes place naturally in cells (“Genetic Engineering”). Restriction endonucleases, which are chemical scissors, are used to separate the DNA molecule at certain points. The first basic step in genetic engineering is to isolate the gene, and insert it in a host using a vector. Then, produce as many copies of that host as possible. Lastly, separate and purify the product of the gene (Batiza 63).…

    • 1334 Words
    • 6 Pages
    Decent Essays
  • Decent Essays

    Although transcription is different in prokaryotes and Eukaryotes, there are many similarities. In transcription in bacteria, transcription officially begins when an RNA polymerase and a sigma subunit bind at two different sites at a promoter. An open promoter complex is formed when DNA unwinds in this area and RNA synthesis starts because of a holenzyme. This is where regulation really comes into play, because transcription will continue as long as it has enough of what it needs until it hits a termination sequence. After which, the brand new produced RNA and enzyme are let go from the template.…

    • 982 Words
    • 4 Pages
    Decent Essays