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Unformatted text preview: 3-point mapLooking at 3 genes (also called this when it happens) so you can get a meaningful orderparental typedouble-crossover typeExactly like it soundspercent recombinationcentiMorganWhat portion of the gametes have been allegated crossover chromosomes? Equal to percentage. Genetic distance, NOT physical distance, because crossing over sometimes happens more often in some species, gender, or area. physical mappingWhat youre seeing: the physical location of these genes influences the genotypes in the gametes that results in mitosis. How? Because the physical distances of the genes create a certain likelihood of crossing over. This can be reserved. If theres a very large skew, you can tell they are closely linked.karyotypeA micrograph in which all the chromosomes within a single cell have been arranged in a standard fashionG-bandingUsed to identify specific chromosomes. In this procedure, chromosomes are treated with mild heat or with proteolytic enzymes that partially digest chromosomal proteins. When exposed to the dye called Giemsa, some chromosomal regions bind the dye heavily and produce a dark band; in other regions, the stain hardly binds at all and a light band results. Though the mechanism of staining is not completely understood, it is thought that the dark bands represent regions that are more tightly compacted. (p 194-195)proteaseGiemsa stainfluorescence in situ hybridization (FISH)In situhybridization can detect the location of a gene at a particular site within an intact chromosome. This method is widely used to cytologically map the locations of genes or other DNA sequences within large eukaryotic chromosomes. The most common method is uses fluorescently labeled DNA probes. Procedure: Chromosomal DNA is denatured into ss regions. SS probe is added. The DNA probe hybridizes to the denatured chromosomal DNA only at specific sites in the genome that are complementary to the probe. A fluorescently labeled molecule that binds to the probe DNA is added. Remember, each x-shaped chromosome contains two copies of a particular chromosome, because they are sister chromatids. (553-555)p and q armsautosomal recessive trait(commonly, affected offspring are produced from unaffected parents)autosomal dominant traitTypically, each affected individual has at least one affected parentX-linked recessive traitMore affected males than females (color blind) and have a general look of recessivenessX-lined dominant traitMore affected females than males and pedigree will have a look of dominanceY-linked traitMust be malemalemale transmission. CANNOT pass through daughtersmitochondrial traitFemale passes to all offspring, males to none (because there is so much mitochondria in the ovum) (Since it looks AD, ALWAYS check ADs to see if...
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This note was uploaded on 04/27/2008 for the course BIO 325 taught by Professor Saxena during the Fall '08 term at University of Texas at Austin.
- Fall '08