CAS BI 107 Lecture Notes - Lecture 4: Phenotypic Plasticity, Apoptosis, Gremlin
Document Summary
Genetic mutations are the source of variation for evolution, however, most mutations affect only a small part of a genome. Genomes of species that appear quite different can be very similar (humans and chimps are identical over 95% of their genome) Transcribed gene products becomes expressed as a phenotype through development. The same gene can accomplish very different things depending on timing, amount, and location of expression. Organisms share similar molecular mechanisms for development that include a toolkit of regulatory molecules that control expression of genes. Toolkit regulatory molecules are able to act independently in different tissues and regions of the body, enabling modular evolutionary change. Developmental differences can arise in changes in the time of regulatory molecule action, the location of its action, or the quantity of its action. Embryological development involves an intricate pattern of sequential gene expression. Control of expression of genes is a result of homologous genes from ancestors.
