Ro_Lecture8

Ro_Lecture8 - Chromosomes and chromosome rearrangements...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Chromosomes and chromosome rearrangements Cytogenetics is the study of chromosomes and chromosome rearrangements. This area of research is germane to several areas of biological research. Cytogenetics has been fundamental to understanding the evolutionary history of a species (for example, although the gorilla and the human are morphologically very different, at the level of the chromosome (and DNA sequence) they are extremely similar. H = human C= chimp G = Gorilla O = Orang utang
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 Chromosomes are classified by size, centromere position and banding pattern: Shown below is the human karyotype (description of the chromosome content of a given species) Karyotype is the chromosome description of length, number, morphology. Karyotype analysis is extremely important in medicine. Alternations in karyotypes are linked to birth defects and many human cancers. Metacentric- centromere in the middle Acrocentric- centromere off center telocentric centromere at one end Karyotype
Background image of page 2
3 Banding patterns Specialized stains produce unique banding patterns along each chromosome. Banding patterns are extremely useful for detecting abnormalities in chromosome structure.
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 The Cri du chat syndrome in humans is a result of a deletion in the short arm of chromosome 5. This was determined by comparing banding patterns with normal and Cri du Chat individuals For many of the chromosome stains the molecular basis of the banding patterns is unclear. Nonetheless these techniques remain fundamental in many areas of genetic research Types of chromosome rearrangements: Deletions, Duplications, Inversions, Translocations
Background image of page 4
5 DDIT Translocation- /P> A____B____C________D____E____F Normal Chromosome Deletions (deficiency) A____B____C________D____F Duplications A____B____C________D____E____E____F Inversions A____E____C________D____B____F A____B____C________D____E____F A____B____C________D____L H____I____J________K____L H____I____J________K____E____F
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
6 Detecting deletions- Deletions are often detected cytologically by comparing banding patterns between the normal and the partially deleted chromosomes However in many instances deletions are too small to be detected cytologically. In these instances genetic criteria are used. Since deletions remove a contiguous set of genes, there is a high probability that an essential gene will be deleted. Therefore deletions will survive as heterozygotes and not homozygotes. A____B________C____D A____B________C____D Normal A____________C____D A____________C____D Homologous deletion (Lethal?) A____________C____D A____B________C____D Heterologous deletion (NOT Lethal)
Background image of page 6
7 B+ A+____/ \_____C+___________D+ A+___________C+___________D+ In individuals heterozygous for the deletion, pairing is disrupted in the regions surrounding the deletion. Therefore recombinant is
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/15/2008 for the course BIO 105 taught by Professor Sullivan during the Fall '08 term at UCSC.

Page1 / 27

Ro_Lecture8 - Chromosomes and chromosome rearrangements...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online