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Which of the following can not be used to determine the physical location of a gene on a chromosome?

1) In Situ Hybridization
2) Somatic Cell Hybridization
3) Three-Point Genetic Cross
4) Deletion Mapping
5) DNA Sequencing

User Borrego
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Final answer:

DNA sequencing cannot be used to determine the physical location of a gene on a chromosome. It sequences the order of nucleotides, but does not reveal the gene's chromosomal locale. Other methods like In Situ Hybridization or Deletion Mapping are appropriate for this purpose.

Step-by-step explanation:

The physical location of a gene on a chromosome cannot be determined using DNA sequencing from the options provided.

DNA sequencing is a powerful tool for determining the order of nucleotides within a DNA molecule, but it does not inherently provide information about the gene's specific physical location on a given chromosome.

The other methods listed - In Situ Hybridization, Somatic Cell Hybridization, Three-Point Genetic Cross, and Deletion Mapping - are all used to ascertain the physical positioning of genes on chromosomes.

To elaborate:

  • In Situ Hybridization uses labeled DNA or RNA probes to locate specific DNA regions on chromosomes by hybridizing to complementary sequences.
  • Somatic Cell Hybridization involves the fusion of cells from different species to determine gene location based on the presence or absence of species-specific traits.
  • Three-Point Genetic Cross is used to determine the order and relative distances between linked genes on a chromosome through recombination frequencies.
  • Deletion Mapping utilizes known deletions within a chromosome to pinpoint the location of a gene by observing phenotypic changes.

Among the methods for creating physical maps, which detail the physical distance between genetic markers, are:

  1. Cytogenetic mapping - Using a microscope to analyze stained sections of chromosomes to determine the approximate distance between genetic markers.
  2. Radiation hybrid mapping - Breaking DNA into fragments with radiation, a technique unaffected by recombination frequency.
  3. Sequence mapping - Employing DNA sequencing technology to create detailed physical maps, which is a separate process from using that technology to ascertain a gene's specific chromosome location.

User Eyalb
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