1. Chapter8 Gene Regulation & Mutations

2. Gene Regulation All cells have all the instructions in their DNA to make all proteins, but they only use the sections of DNA or genes that they need. -Promoters are essential to the initiation of transcription -Regulatory sites also exist near the promoter that can regulate transcription -These proteins can decide whether a gene gets turned on or off *Makes gene expression a regulated process

3. Gene Regulation Examples in organisms: Prokaryotes – contain operons which are groups of genes that operate together -presence of a certain sugar or protein will activate transcription and the gene will be expressed -repressor proteins exist that can inhibit transcription and turn the gene off

4. Gene Regulation Eukaryotes : - no operons - utilize a DNA sequence called a TATA box that helps position RNA polymerase after promoter sequence - other enhancer sequences exist to regulate transcription- wide variety of protein binding can take place - DNA binding proteins can still block access to genes and act like a repressor

5. Differentiation Eukaryotic differences: *Cell specialization requires genetic specialization - During embryonic development cells differentiate – meaning they will specialize in structure and function to an area of the body needed Hox genes- series of genes that develop in the embryo and serve master control genes of differentiation *mutation to a hox gene will completely change the organs in specific parts of the body ex: fruit fly with legs on head instead of antennae

6. Epigenome The epigenome consists of chemical compounds that modify, or mark, the genome in a way that tells it what to do, where to do it, and when to do it. Different cells have different epigenetic marks. The environment causes changes in our epigenetics. http://video.pbs.org/video/1525107473#

7. Development and Differentiation Similarities exist in the way organisms regulate genes *Transcription is the regulating process which will determine what is turned on and off -series of genes work together to shape the organism (either operons or hox type genes) -common patterns of genetic control exist because all these genes descended from one common ancestor

8. MuTaTiOnS Mutations- changes in the genetic material - caused by mistakes in copying DNA - skipped base or incorrect bases can slip by undetected by the proofreading polymerase - can be product of a single gene or a whole chromosome

9. Types of Mutations Gene Mutations 1. Point mutations 2. Frameshift mutation Chromosomal Mutations 1. Deletion 2. Duplication 3. Inversion 4. Translocation

10. Gene Mutations Point mutation – change in one of the base pairs in the sequence Ex: substitution of a base will change the amino acid that is coded The fat cat ate the wet rat. The fat cat ate the wee rat. What kind of effect would result? Overall effect may not even be noticeable or change anything about the cell

11. Gene Mutations Frameshift mutations - alteration of the reading frame of the genetic message from the insertion or deletion of a nucleotide. Insertion – adds an extra codon or base in original sequence The fat cat ate the wee rat. The fab tca tat eth ewe era t. Notice any changes?

12. Gene Mutations Deletions – removes a codon or base from the sequence The fat cat ate the wee rat. The fat cat att hew eer at. Where is the change? Will these be the same amino acids?

13. Chromosomal Mutations Involves changing the number or structure of the chromosome -can change the location of certain genes and even the number of copies of that gene

14. Chromosomal Mutations 4 types of mutations: 1. Deletions- involve loss of all or part of chromosome 2. Duplication – produces extra copies of parts of the chromosome 3. Inversions – reverses the direction of parts of the chromosome. The fat cat ate the wee rat. The fat tar eew eht eta tac. 4. Translocation – part of one chromosome breaks off and attaches to another. The fat cat ate the wee rat. e the wee rat.The fat cat at

15. Overall Result Mutation will improperly group codons downstream unless at the end, will likely produce a nonfunctional protein it may be transmitted to offspring and to future generations If adversity is great enough to effect the phenotype of organism it is referred to as a genetic disorder