GEN-3000 Lecture Notes - Lecture 6: Robertsonian Translocation, Dosage Compensation, Aneuploidy
Document Summary
Tandem vs. displaces duplication: duplicated region is immediately adjacent (t) or located some distance (even on different chromosome (d) Loop formed during meiosis is characteristic of duplication. **-unequal crossing over (once duplication it becomes easier to have more duplication events) Gene dosage: balance of gene products muscat be maintained for some pathways. Deletion of centromere leads to loss of the chromosome (no segregation in meiosis/mitosis) Loss of essential genes: lethality if homozygous for loss. Formation of deletion loop during paring of homologs in prophase i. Paracentric inversion: inversions that do not include centromere. Inversions-gene order is changed, can break a gene in two. Regulation of fences is sometimes context dependent - position effect. Elimination or reduce crossing over: chromosomal rearrangements. Human aneuploidies: aneuploids- the number of chromosomes is altered (addition/deletion) chronometer is not tetrasomydouble trisomic!) Nonreciprocal translocation=movement one way, from one chromosome to another without equal exchange. Reciprocal translocation=both chromosomes have broken and exchanged information.
