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The ordinary segregation pattern of an allele pair (Aa) among the 4 products of meiosis is 2A:2a. Detection of infrequent gene conversion events (e.g. 3:1 or 1:3 segregation patterns during individual meioses) provides insight into the alternate pathways of recombination leading either to crossover or non-crossover chromosomes.
Because the point mutation lies within the deletion of del-1, there will be no wild-type (+) recombinants between the point mutant and the del-1 mutant. However, in a cross between the point mutant and the del-2 mutant, there could be a successful wild-type (+) recombinant produced.
In the more scaled-down 384-well plate microfluctuation method the frequency of mutation is counted as the number of wells out of 48 which have changed color after 2 days of incubation. A test sample is assayed across 6 dose levels with concurrent zero-dose (background) and positive controls which all fit into one 384-well plate.
Deletion on a chromosome. In genetics, a deletion (also called gene deletion, deficiency, or deletion mutation) (sign: Δ) is a mutation (a genetic aberration) in which a part of a chromosome or a sequence of DNA is left out during DNA replication. Any number of nucleotides can be deleted, from a single base to an entire piece of chromosome. [1]
Types of mutations that can be introduced by random, site-directed, combinatorial, or insertional mutagenesis. In molecular biology, mutagenesis is an important laboratory technique whereby DNA mutations are deliberately engineered to produce libraries of mutant genes, proteins, strains of bacteria, or other genetically modified organisms.
Saturation mutagenesis is commonly achieved by site-directed mutagenesis PCR with a randomised codon in the primers (e.g. SeSaM) [2] or by artificial gene synthesis, with a mixture of synthesis nucleotides used at the codons to be randomised. [3] Different degenerate codons can be used to encode sets of amino acids. [1]
Gene knockout by mutation is commonly carried out in bacteria. An early instance of the use of this technique in Escherichia coli was published in 1989 by Hamilton, et al. [2] In this experiment, two sequential recombinations were used to delete the gene.
Early attempts at mutagenesis using radiation or chemical mutagens were non-site-specific, generating random mutations. [2] Analogs of nucleotides and other chemicals were later used to generate localized point mutations, [3] examples of such chemicals are aminopurine, [4] nitrosoguanidine, [5] and bisulfite. [6]