GN 311 Lecture Notes - Lecture 10: Robertsonian Translocation, Chromosomal Translocation, Philadelphia Chromosome
Document Summary
Reciprocal translocations: no gain or loss of dna, two nonhomologous chromosomes exchange arms. Non-reciprocal translocations: no overall gain or loss of dna, part of one chromosomes is moved to a non-homologous chromosome. Robertsonian translocations: two chromosomes squished together. Isochromosomes- two chromosomes joined are homologs: familial down syndrome can be due to either robertsonian translocation or isochromosmes. Joining between chromosomes 14 and 21: only occurs in 4% of down syndrome cases. We cannot have major duplications or translocations, like we do under the adjacent- Chimpanzees have 48 chromosomes because there was a robertsonian translocation in hu(cid:373)a(cid:374)s" a(cid:374)(cid:272)estors. 90% of patients have the philadelphia chromosome. Fatal uncontrolled replication of myeloid stem cells. Moves myc gene by the immunoglobin gene: myc makes protein to watch over cell division, usually tightly regulated, which immunoglobin is not. B cells make a lot of immunoglobin. The cell is basically dividing way more often than it should be. Too many copies of chromosomes i. e. down syndrome.
