Biology 1201A Lecture Notes - Lecture 2: Dna Replication, Gametophyte, Sporophyte

• School: Western University
• Department: Biology
• Course: Biology 1201A
• Professor: Jennifer Waugh

Document Summary

At the level of an organism, it is important that all individual cells in the body are genetically identical. For a population, it is important that individuals are genetically different from one another. If populations have genetic variability, they have the potential to evolve. Ultimate source of genetic diversity is mutation of the dna sequence, usually from errors during replication. Genetic recombination: cutting and pasting sequences of dna into new combinations: reproduction is asexual without genetic recombination, offspring would be identical clones to their parents. Genetic recombination requires: two dna molecules that differ from another, a mechanism for bringing the dna molecules into close proximity, e(cid:374)z(cid:455)(cid:373)es to (cid:862)(cid:272)ut(cid:863), (cid:862)e(cid:454)(cid:272)ha(cid:374)ge(cid:863), a(cid:374)d (cid:862)paste(cid:863) the dna (cid:271)a(cid:272)k together. Sugar-phosphate backbone is held together by strong covalent bonds. The hydrogen bonding if base pairs is relatively weak. Regions of dna that are similar but not identical, the regions can be short or long homologous chromosomes.