Genetics FInals

Point mutations

that is changes at the base pair level within a gene or its control regions

transition mutation

occurs when one purine is replaced by the other purine (A ↔ G), or one pyrimidine is replaced by the other pyrimidine (T ↔ C)

transversion mutation

a purine is replaced with a pyrimidine, or vice versa

Silent Mutation

often have no effect on the amino acid that is incorporated into the final protein

Missense mutation

a change in an amino acid

Non sense mutation

. A base change that results in a stop codon (UAA, UAG, or UGA)

frameshift mutation

can dramatically alter the amino acid makeup of the protein. It also often results in a stop triplet (a nonsense mutation) soon after the point of the frameshift and leads to early termination of translation

Neutral mutation

A change from one small hydrophilic amino acid to another in a non active part of the protein is a real change, but it is unlikely to have much impact

Mutation frequency

refers to the proportion of alleles of a given type in the gene pool.

Mutation rate

refers to the rate at which new mutant alleles are formed, and it is reported at different scales.

Genetic damage rate

is the rate at which errors occur during the process of DNA replication

mutational event rate

measures what is left after repair has taken place.

Polymorphism

occurs when the most common allele is at a frequency of less than 99%. any gene or nucleotide in which more than one form is found in the population

Depurination

an adenine or a guanine base is removed from a nucleotide, leaving the sugar phosphate backbone intact, and the partner nucleotide temporarily unpaired.

Deamination

occurs when an amino group is removed from cytosine, produces uracil

Tautomeric Shifts

involves a reversible change in hydrogen that alters the nucleotide base to a different isomer.

Germinal mutations

passed in eggs or sperm to affect development of an offspring

Somatic Mutations

mutations in cells within the body well after birth

Molecular Decay

The assumption is that over time, with enough replications, a mistake will eventually occur for no apparent reason

Mutagens.

are any agent that can induce or increase the overall rate of new mutations

Carcinogen

is an agent that can induce or increase the risk of cancer

Teratogens

are external agents that can result in congenital anomalies if a developing fetus receives a significant exposure

pedigree

a series of Mendelian genetic crosses involving relatives

Proband

is the first member in a family to be evaluated by the physician

First Degree

parents, siblings, offspring of the proband

Second Degree

grandparents, grandchildren, uncles, aunts, nieces, nephew

Third Degree

cousins, etc.

Consanguinity

is defined as the mating of two closely related individuals

Deleterious mutation

The amino acid mutation wherein one or more nucleotides are missing, altering biological functions

Deletion Mutation

The frameshift mutation wherein it deletes a nucleotide, resulting in a backward shift

Ames Test

Uses back mutation. Culture bacteria having nutritional deficiency. Very effective assay for potential mutagenic agents

Seven locus test

Seven easily identifiable recessive mutations. It is more expressive

X linked lethal assay

X rays are mutagenic. Used to screen for hazardous mutagenic chemicals from industrial by products and for other experimental questions