Mutations-Exam_2_bio_gentics

Mutation

The process of alteration of a gene or chromosome, producing a change in a phenotype.

Haplotype

A particular DNA sequence that differs by one or more mutations from homologous sequences.

Mutationist Theories

Theories proposing that new species can arise by mutations, suggesting that drastic genomic changes can create new higher taxa.

Point Mutation

A mutational event involving substitution, deletion, or insertion of a base pair.

Missense Mutation

A mutation that results in a change from one amino acid to another.

Nonsense Mutation

A mutation that changes an amino acid codon into a stop codon, terminating protein synthesis.

Simple Substitution

A mutation where one nucleotide is replaced by another, which can have various effects on translation.

Transposable Elements

Normal components of genomes that can move within the genome, potentially altering gene function.

Spontaneous Mutation

Mutations that occur without special agents, often due to DNA replication errors.

Suppressor Mutation

A mutation at a different site that compensates for the negative effects of an original mutation.

Neutral Mutation

A mutation that does not affect the function of the encoded protein.

Base Excision Repair

A mechanism for repairing damaged DNA where incorrect bases are removed and replaced.

Nucleotide Excision Repair

A DNA repair mechanism that corrects the mutations caused by distortions in DNA.

Methyl-Directed Mismatch Repair

A repair process where mismatched bases are corrected based on the methylation pattern of DNA.

Thymine Dimers

DNA lesions caused by UV light that result in covalent bonding of adjacent thymine bases.

Transition Mutation

A type of point mutation where a purine is replaced with another purine or a pyrimidine with another pyrimidine.

Transposons

Complex transposable elements that can insert themselves into new genomic locations, potentially disrupting gene function.

Locus

The specific location of a gene on a chromosome.

Cumulative Effects of Radiation

The long-term consequences of radiation exposure that worsen over time.

Adaptation Theory

The theory that mutations occur randomly and are not directed by environmental needs.

Gene Regulation Mutation

Mutations that occur in regulatory regions affecting the expression of genes.

Richard Goldschmidt (1878-1958)

A geneticist -one of the first scientist to integrate genetics, development and evolution

Hopeful Monster

A term coined by Richard Goldschmidt to describe a significant evolutionary change that occurs through large mutations, leading to new species.

Charles Darwin (1809-1882)

Differential survival due to natural selection

Heritable variation

Heritable adaptive variation is due to random mutations

Average human mutation rate

1 in 30 million base pairs (very low)

Diploid genome has 6.6X 10^9 bp, so average zygote has?

220 new mutations

only 2.5% of genome has functional, transcribed genes, so average human zygote carries about ?

6 mutations that are potentially harmful

Chromosomal mutation

mutational event involving chromosomal deletion, insertion or rearrangement

Point mutation result in?

(changes function of gene) only if they occur in coding region of gene or regulating sequences

Somatic mutations

occur in somatic cells and only affect the individual in which the mutation arises

Germ line mutations

Alter gametes and passed to the next generation

transition mutations occur at?

nucleotide base pairs where a purine is replaced by another purine or a pyrimidine by another pyrimidine.

Base pair substitution

a type of mutation where one nucleotide base is replaced by another, potentially altering the amino acid sequence of a protein.

Synonymous

mutation that does not change the amino acid sequence of a protein due to redundancy in the genetic code.

Nonsynonymous mutations

are mutations that result in a change in the amino acid sequence of a protein, potentially affecting its function.

Tautomer

different chemical states of nitrogenous bases

Tautomers normal state

Keto form

Enol Form

is a tautomer of a ketone where the hydroxyl group is attached to a carbon atom that is double-bonded to another carbon atom.

Hydroxyl group (OH) affixed to a carbon with a double bond

Imino form

Double bond migrates and moves position of hydrogen bonds

They can cause unusual base pairing, leading to mutations

Enol and Imino forms