Chapter 23 Flashcards
learning objective
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learning objective
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mapping
refers to experimental process of deeming the relative locations of genes or other segments of DNA along individual chromosomes
cryogenic mapping
determines locations of specific sequences within chromosomes through staining and binding pattern and are mapped relative to band location
linkage mapping
use the frequency of genetic recombination between different genes to determine their relative spacing and order along a chromosome
physical mapping
DNA cloning techniques are used to determine the location of and distance between genes and other DNA regions
genetic/chromosome map
a diagram that describes the relative locations of genes or other DNA segments along a chromosome
locus/loci
refer to the site within a genetic map where a specific gene or other DNA segment is found
23.2 learning objective
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learning objective
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what does cryogenic mapping do?
determines the locations of specific gene sequences within chromosomes that are viewed microscopically
what are some key differences between eukaryotic chromosomes and bacterial chromosomes?
eukaryotic chromosomes are bigger in size, centromeric location, and different banding patterns
what is one limitation of cryogenic mapping?
it uses light microscopy, so it has limited resolution and can only do about 5 million bp along a chromosome
in situ hybridization
is used to cryogenically map the locations of genes or other DNA sequences within large eukaryotic chromosomes
- situ means the chromes are held in place
- hybridization means a hybrid forms
what does it mean to use a labeled probe?
can use a piece of cloned DNA as a probe so it will complementary attach to the gene of interest
what is FISH?
fluorescence in situ hybridization
what are the steps of the fish procedure?
1) treat cells with agents that make them swell and fixes them onto a slide
2) Denature chromosomal DNA
3) Add single stranded DNA probes that have biotin
4) add fluorescently labeled Alvin that binds to biotin
5) view with a microscope
what is the goal of FISH?
determine the location of the gene within a set of chromosomes
what is the purpose of biotin?
it has a high affinity for a protein called Advin, so when fluorescent Advin is added, it binds with biotin labeled nucleotides and labels the probe
what kind of microscope needs to be used?
fluorescence microscope
what is a common dye used in FISH?
DAPI - it is a fluorescent dye specific for DNA
chromosome painting
using fluorescently labeled probes to identify multiple regions along one ore more chromosomes