Biology 1201A Lecture Notes - Lecture 3: Copy-Number Variation, Tandem Repeat, Transposable Element
18 Dec 2017
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Topic 3: generating diversity origins of variation, new alleles. Structural variation: changes in the physical arrangement of gene or sequences on chromosomes. Copy number variation (cnv): individuals vary due to the varying numbers of each gene in each unique person. Homologous chromosomes: in reality are not the exact same, they may have slightly different patterns of genes. **still act as homologous chromosomes in mitosis / meiosis. These differences often occur due to structural variations. Slippage in replication: newly synthesized dna (or template strand) slips, looping out bases. Often in tandem repeat regions expanding the size of the repeats. When this loop of extra nucleotides goes through replication it creates a tandem duplication of the sequence. This slippage can cause the repeating or skipping/deleting of a sequence. Mobile/transposable elements: dna segments that move within the genome. Transposase identifies inverted repeat sequences (ir) at end of an element. Transposase cuts/copies and pastes the transposable elements to other chromosomes.
