Lecture 5 study guide Flashcards
Polymorphism
The occurrence of different forms among the members of a population, can be morphological, genetic, behavioral, physiological
Genotype
The genetic constitution of an individual organism
Phenotype
the expression of the genotype of an organism, may be influenced or even determined by the environmental conditions experienced by the organism
Mutations
the prosses of alteration of a gene or chromosome and its product
DNA
a serise of nucleotide base pairs
Purines
The base pairs adenine and guanine
Pyrimidines
the base pairs thymine and cytosine
chromosomes
a single long coiled molecule of DNA
gene
a sequence of DNA that is transcribed into RNA
transcription
the proccess by which DNA is convered to RNA
Translation
the procces which RNA is convered to protine
Locus
a site on a chromosome occupied by a particular gene or base pair region
exons
gene segments that code for a protine
introns
non coding DNA segments that occur between exons
Codon
a 3 base pair segment of RNA that codes for a particular protine
Amino acids
the building blocks of protines that are linked together to form a polypeptide, coded for by RNA
Allele
different forms of a gene
Haplotype
A particular DNA sequence that differs by one or more mutations from homologous sequence
Genetic Markers
Detectible mutations that geneticists use to recognize specific regions of chromosomes or genes
Fixed
A mutation that has increased in frequency to the point that it is found in every individual in a population
Wild Type
Fixed genes reflecting the typical genotype or phenotype of a population
Base Pair substitution
a mutation that maps to a single locus often restricted to a single base pair
transition
a type of base pair substitution whereby a pruine is substituted for a purine or a Pyrimidine for a pyrimidine
Transversion
A type of Base pair substitution whereby a purine is substituted for a pyrimidine or vise vera
Synonomous mutations
Mutations that have no effect on the resulting amino acid, polypeptide, or protein
Nonsynonymous mutations
Mutations that result in amino acid substitutions thereby changing the structure and function of the resulting protine
dn/ds ratio
the number of nonsynonymous mutations divided by the number of synonymous mutations, when the ratio is less then 1 nonsynonymous mutations are deleterious and removed by purifying selection, when the ratio is equal to 1 mutations are evolving neutrally, when its greater then 1 many of the nonsynonymous mutations were fixed by positive selection
Frameshift mutations
a mutation that causes a shift in the reading frame such that the identity of amino acids occurring downstream of the mutation may be changed, the resulting polypeptide is usually greatly altered
Insertion
a mutation whereby a single base pair is inserted into a DNA sequence
Deletion
A mutation whereby a single base pair is deleted from a DNA sequence
Recombination or crossing over
A normal process where genes are exchanged between chromosomes during meiosis
Unequal crossing over
when 2 chromosomes are not perfectly aligned, results in tandem duplication on one chromosome and deletion on the other
Pleiotropy
occurs when multiple phenotypic traits are affected by a single mutaiton
Karyotpe
A description of the complement of chromosomes that includes number, size, shape, and internal arragnement
Aneuploidy
unbalanced chromosome complement, usually results in inviability or poor development
Polyploidy
changes in the number of whole sets of chromosomes
Diploid
an organism with two entire sets of chromosomes
polyploid
an organism with more then two sets of chromosomes
