Class Recap: 4/8/11

Hi Class, today we went over changes in chromosome structure and how these structural changes come about and the consequences of these changes. ***For those of you who missed class today, homework is listed at the end of the post. You have three days from the time you return to school to hand in missing work.

VOCABULARY
inversion (paracentric or pericentric)
deletion
duplication
reciprocal translocation
non-reciprocal translocation
Robertsonian Translocation

Intro: We know from yesterday's lecture that changes in the number of chromosomes can have dire effects on an individual. Today in class we learned about the effects of changes in chromosome structure.Much like changes in chromosome number, changing the structure of a chromosome can also produce some nasty effects. In class, we talked about inversions, deletions, duplications, and translocations.

Chromosomal inversions are chromosome rearrangements in which a segment of a chromosome is reversed end to end. Inversions occurs when a single chromosome undergoes breakage and rearrangement within itself. There are two types of inversions: paracentric and pericentric.

Chromosomal deletions occur as a result of a mutation that causes a segment of a chromosome (and the information contained in that segment) to be lost. Two types of deletions are terminal deletions and interstitial deletions.

Chromosomal duplications occur when any segment of DNA that contains a gene is doubled. Some types of duplications include tandem duplications, reverse tandem duplications, and terminal tandem duplications (see page *** of your textbook for pictures).

Chromosomal translocations are caused by rearrangement of parts between non-homologous chromosomes. The three major types of translocations are: reciprocal translocations (mutual exchange of parts), non-reciprocal translocations (non-mutual exchange of parts), and Robertsonian translocations (two acrocentric chromosomes that fuse near the centromere region with loss of the short arms).

The following video will provide a review of these terms we just went over and allow you to have a better picture of each of these chromosomal structural changes.

***HOMEWORK***
-Worksheet on chromosomal abnormalities
-Do questions 2-8, 11-13, and 18 on page ***