Mutations: Types and Effects PDF

**What are mutations, how do they occur and what are the effects?** *[How do they occur?]* - Spontaneous - Errors in replication - Radiation, chemicals Mutation= base pair sequence is altered Cell with mutation= mutant cell=\>heritable changes *[Types mutations ]* Somatic mutations= mu...

**What are mutations, how do they occur and what are the effects?** *[How do they occur?]* - Spontaneous - Errors in replication - Radiation, chemicals Mutation= base pair sequence is altered Cell with mutation= mutant cell=\>heritable changes *[Types mutations ]* Somatic mutations= mutation in somatic cell=\> affects only the individual =\>not passed to other generations Germ-line mutations=\> mutation in sexually reproducing organisms=\> transmitted by gametes to next generation. *[Different gene mutations ]* - Substitution (base-pair) - Missense: change in mRNA codon = different amino acid inserted in polypeptide =\>phenotypic change may or may not result (depends on the type of change) - Nonsense mutation: base-pair change results in altering mRNA codon in a stop codon=\>causes premature termination of synthesizing polypeptide chain (often nonfunctional polypeptide chains) - Neutral mutation: changes codon in mRNA =\> no detectable change in the function of the protein (=missense mutation where the new codon codes for a chemically equivalent amino acid) - Promotor mutation: block/ activate transcription - Splice site: blocks splicing or can create new splicing signals (can cause part of a protein to be deleted) - Silent mutation: altered codon in the mRNA specifies the same amino acids in the protein - Difference silent and neutral mutation: A **silent mutation** specifically does **not change the amino acid** sequence of a protein, and is therefore one type of neutral mutation. - Back mutation= reverse mutation -\>back to original gene after a mutation *(also the model to correct this jukes-cantor model=\>amount of mutations you see is not amount of mutations that occurred =\>calculate how many mutations really occurred )* - Insertion/deletion (base pair) Frameshift mutations-\>base pair added or removed from a protein-coding gene -\> reading frame mRNA can change downstream of the mutation. =\>incorrect amino acids can be added/ shortened polypeptide chain / nonfunctional polypeptide chain/ longer polypeptide chain =\>polypeptide chain effected by any number of deletions/insertions that are NOT dividable by 3. =\>wild type: term describing an allele or phenotype that is designated as the standard for an organism and is usually most relevant in a wild population, also used as reference - Point mutations 2 classes: forward mutation (changes wild type to a mutant gene) and reverse (changes mutant gene at same site so it functions in a completely wild type or nearly wide type way) =\>true reversion= back to wild-type amino acid =\>partial reversion= reversion to other amino acid - Suppressor mutation=\> masks or compensates for the original mutation (DOES NOT reverse the mutation) =\>usually at second site + can restore or partially restore the initial function of the protein \[2 types: intragenic (occurs within same gene ) and intergenic (occurs in different gene) \] - Visible mutation=\> affects the morphology/visual appearance of organism - Auxotrophic mutation =\>effect on growth cell - Conditional mutation=\>mutation that results in the wild-type, but under certain conditions (e.g. temperature sensitive mutations) - Loss of function mutation=\> leads to absence/deceased activity of protein (usually recessive) - Null mutation=\> results in protein with no function (reduces expression of gene to zero) - Spontaneous mutation=\> occurs naturally during DNA replication or other stages of cell growth and division - Induced mutation=\> happens when organism is exposed to chemical or physical agent (=mutagen). The mutagen interacts with the DNA - Homeotic mutation=\> mutation that alters identity of certain body segment. -\>transforms it into a copy of different segment - Lethal mutation=\> causes cell death - Frame mutation=\> insertions or deletions of multiple of 3 base pairs-\> causes reading frame to shift - Chromosomal mutations - Changes in parts chromosome or whole chromosome - Both eukaryotes and prokaryotes - Spontaneous or induced - Deletion=\> part of chromosome is missing (starts with breaks in chromosome induced by e.g. heat, viruses, chemicals,... - Deletion that involves loss of the CENTROMERE=\> result= acentric chromosome - Terminal= deletion that occurs towards end of chromosome - Micro= small deletion - Interstitial= occurs from interior of chromosome - Duplication=\> doubling segment of chromosome - Tandem duplication= duplicated segments that are adjacent to each other - Reverse tandem duplication= order of genes duplicated is opposite of the original order - Terminal tandem duplication= duplicated segments are arranged in tandem at end of chromosome - Heterozygous duplications= results in - Inversions=\> segment of chromosome is inversed 180 degrees. - Paracentric inversion= doesn't include centromere - Pericentric inversion= does include centromere - Translocations=\> change of segment chromosome to a different location in genome - *Nonreciprocal intrachromosomal= changes position within same chromosome* - *Nonreciprocal interchromosomal= changes position from one chromosome to another* - *Reciprocal interchromosomal= two segments from different chromosomes switch with each other* Afbeelding met tekst, schermopname Automatisch gegenereerde beschrijving **What are phylogenetic trees + how to make a phylogenetic tree?** = graphic representation of evolutionary relationship between among group of species/genes. Branches represent ancestral organisms. *[2 methods]* - UPGMA  **The phylogenetic tree for cats, dogs, humans and chimpanzees**