GENE 320 Lecture Notes - Lecture 17: Chorionic Villus Sampling, Statistical Hypothesis Testing, Trisomy
Document Summary
Responds after damaged dna has escaped repair and has failed complete replication. Reca protein directs recombination exchange with corresponding region on undamaged parental strand. Gap can be lled in by repair synthesis. Rare genetic disorder due to defects in ner (nucleotide excision repair) pathways affected individuals exhibit severe skin abnormalities, skin cancers, developmental and neurological defects. Both strands of the dna sequence are broken, so there is no complementary strand to replicate off of. This can lead to the downstream part of the sequence to fall off and not appear at all. Alterations of chromosomes total amount of genetic information in chromosome changes. Represent quantitative differences in number of large dna sequences. Found in coding and noncoding regions of genome. Duplications are the primary source of new genes in genomes: evolution of the human a- globin and b-globin gene families. Increase in gene number is due to duplications of genes and genomes.