Lecture 5 Flashcards
1
Q
Evolution requires
A
Variation
2
Q
Polymorphism
A
Resulting in mimics by the species, occurs in areas of overlap
3
Q
Evolution is impossible without
A
Variation
4
Q
Genotype gives rise to
A
phenotype
5
Q
Genotypic differences are partily responsible for
A
phenotypic differences
6
Q
Phenotype can also be influenced by
A
Enviorment
7
Q
Mutation is responsible for
A
differences in genotypes
8
Q
Mutation gives us
A
Variation
9
Q
Genome of all organisms consits of
A
DNA
10
Q
DNA is
A
A serise of nucleotide base pairs
11
Q
Base pairs are
A
a purine and a pyriminde
12
Q
Purines are
A
Adenine and Gyanine
13
Q
Pyrimidines are
A
Thymine and cytosine
14
Q
DNA ladder
A
Phosphate is the backbone, base pairs are the rungs
15
Q
DNA varation
A
Varys greatly amoung organisms, genome size doesnt corilate with complexity
16
Q
Chromosome
A
One long DNA molecule coiled
17
Q
Gene
A
Sequence of DNA that is transcribed into RNA
18
Q
RNA is translated into
A
Protine
19
Q
Locus
A
site on a chromosome occupied by a particular gene
20
Q
Exons
A
Gene segments that code for a protine
21
Q
Introns
A
Noncoding segments that occur between exons
22
Q
Codon
A
3 basepairs of RNA, codes for specific protine
23
Q
Amino acids
A
Building blocks of protines
24
Q
How many possible codons and amino acids
A
64 codons, 20 amino acids, genetic code is redundant
25
3 codons are
stop codons
26
Alleles
Different forms of a gene
27
Alleles can code for
different phenotypes of the same trait like fur color
28
Alleles identified by
phenotype effect, but not all alleles have a phenotype effect
29
Haplotype
Particular DNA sequence that differers by one or more mutations from homologous sequence
30
Genetic markers
Detectable mutations that geneticits use to recognize specific regions of chromosomes or genes
31
Mutation
Alteration of a gene or chromosome and its product, DNA can be damaged by chemical and physical events
32
Mutations result in
change in base pair sequence, many changes are repaired by DNA polymerase
33
DNA polymerase
proof reading enzyme
34
Germline cell
Sex cells
35
Mutations only occur in
a single cell of a single organism
36
If mutation is in the germ line
it can give rise to a single gamete with that mutation, if its a precursor to germ line several gametes may carry the mutation
37
Initilly the mutation is
carried in very small proportion to population
38
Mutations can become
Fixed in the population due to natural selection or genetic drift
39
Fixed
carried by almost the whole population
40
fixed genes represent
the current wild type
41
most mutations do not
become fixed
42
Mutations must happen in ------ to be passed on
germ line cells
43
Varriation arises from 2 sources
point mutations and sequencing changes arising from recombination
44
Point mutations are
single changes in DNA
45
sequence changes are
whole sequences of DNA changed all at one
46
Mutations can have a phenotypic effect if
the occur in genes that encode molecules involved in transcription/translation, regulatory DNA regions, and protein encoding regions
47
Recombination
shuffles existing, makes new allele combos
48
Base pair subsitutions
maps to a signle locus, offten restricted to a single base pair, can be transition or transversion
49
transition
A substitution of a purine for a purine G for A or a pyrimidine for a pyrimidine T for C, this is more likely than transversion
50
Transversion
a substitiution for a purine for a pyrimidine G for C
51
Synonymous mutations
Have no effect on the resulting amino acid, polypeptide, or protein
52
Nonsynonymous mutations
Result in amino acid substitution, codon changes substantially
53
DnDs ratio
Number of nonsynonymous mutations divided by number of synonymous mutations, can be used as indicator for natural selection
54
DnDs < 1
Most nonsynonymous mutations are deleterious and removed by purifying selection
55
DnDs= 1
Nonsynonomous and synonymous mutations are evolving largely neutrally
56
DnDs>1
many of the nonsynonomous differences between the species were fixed by positive selection
57
Frameshift mutation
insertion or deletion, resulting polypeptide is useually greatly altered, protine non functional
58
Insertion
a single base pair is inserted
59
deletion
a single base pair is deleted
60
Recombination
a normal process where genes are exchanged between chromosomes during meiosis
61
Unequal crossing over
When 2 chromosomes are not perfectly aligned, results in tandem duplication in one chromosome and deletion in the other, can range in size from single bp to whole segment
62
unequal crossing over usually occurs in
areas that already has tandem repeats, generate a large number of nonfunctional sequences, increases total length of dna
63
mutation is the ultimate sourse of
variation
64
another contribution to variation is
gene mixing through segregation and recombination durring meiosis, shuffles existing variation to create new gene combos
65
Non sexually reproducing organisms
horizontal gene transfer creates new gene combonations
66
without sources of variation
evolution wouldnt be possible
67
Effects on mutation are variable, depend on
where in the genome the mutation happens and the phenotypic trait that is affected
68
Pleiotrophy
multiple traits could also be effected
69
Rates of mutation are
difficult to measure due to mutations being synomyous and death or carriers
70
Rates will be different in
protein coding vs non protine coding regions
71
We used to rely on changes in phenotypes for rates of mutation
now we rely on DNA sequences
72
each human carrys around --- mutations
70
73
mutation is a
random process, not all loci regions are equally mutable tho
74
The process of mutation is
stochastic rather then deterministic, we can determine probability of mutation occurring but we cannot predict which of a large number of gene copies will undergo mutation
75
Chance of a particular mutation will occur is not influenced by whether or not
the organism in an environment in which that mutation would be advantageous
76
Mutation rates may be elected by certain stressful environments but
environment cannot elect advantageous mutations
77
Karyotype
a description of the complement of chromosomes, includes number, size, shape, and internal arangement
78
Aneuploidy
unbalanced chromosome complement, usually results in inability or poor development
79
Polyploidy
changes in whole sets of chromosomes
80
diploid
organisms with 2 entire sets of chromosomes
81
polyploid
organism with more then 2 sets of chromosomes
82
Triploid zygots produce
aneuploid gamets, usually produce few offspring as result
83
Gametes of different ploidy levels may produce
different zygots that are 6N, 8N, ect
84
Polyploid may result in
instantaneous speciation, opens the possibility of multiple origins for a single species
