Exam #2 Flashcards
(123 cards)
1
Q
50% Recombinant frequency observed in testcross =
A
genes likely to be carried on the same chromosome
2
Q
Linked genes do not follow what law?
A
Law of independent assortment
3
Q
Linked genes do follow this law..
A
Chromosomal basis of inheritance
4
Q
1990 Bateson and Punnett did what..
A
Re-discovery of Mendel’s data and new data
Certain pea dihybrids not 9:3:3:1
5
Q
1910 T.H. Morgan
A
Proposed “linkage” as an explanation for Drosophila data
centiMorgans
6
Q
NOT 1:1:1:1 means..
A
linked genes
7
Q
Parental types should represent ______ of total testcross progeny
A
> 50%
8
Q
Two equally frequent non-recombinant classes
A
> 50%
9
Q
Two equally frequent recombinant classes
A
<50%
10
Q
Recombinants for linked genes are produced by _____________
A
crossing over
11
Q
Homologous chromosome pairs align in this stage of meiosis
A
Prophase I
12
Q
__________ form between two non-sister chromatids
A
Chiasmata
13
Q
Neurospora Tetrad Analysis
A
Meiosis forms 8 daughter cells (octad)
Tetrad daughter cells from meiosis II
14
Q
Linked genes in a dihybrid can exist in these two conformations..
A
cis and trans
15
Q
cis
A
AB/ab
16
Q
trans
A
Ab/aB
17
Q
alleles on same chromatid have ____________ between them
A
no punctuation
18
Q
Slash seperates…
A
members of homologous pair
19
Q
Map units are based on…
A
recombination frequencies
20
Q
Map units represent
A
hypothetical distances
21
Q
Genetic and physical distances are…
A
correlated
22
Q
Other factors in genetic vs. physical distances
A
hotspots or blocks
23
Q
Most rare…
A
Double Recombinants
24
Q
Compare double recombinants to parentals to determine….
A
gene order
25
Crossovers at one position interfere with the frequency of...
other crossovers occurring nearby
26
Crossovers _______ other crossovers
inhibit
27
Male fruit flies ____________ undergo crossing over
do not
28
All male fruit flies are of the ____________ type
parental
29
Molecular variations may not affect
phenotype
30
SNPs
most of the differences between individual DNA sequences
Abundance and distribution make them usefule for fine-scale mapping
31
RFLPs
Restriction Fragment Length Polymorphisms
32
SNP in DNA sequence alters....
site-specifit activity of restriction enzymes
33
Haplotype mapping
Refer to powerpoint
34
QTL mapping
refer to powerpoint
35
Eukaryotic genetics...
Linear chromosomes in nucleus
36
Prokaryotic genetics
genetic material is free floating in cytoplasm
| circular bacterial chromosome
37
Bacteria features
Lack nuclear membrane
lack membrane bound organelles
chromosomes fold to form nuclear body
most have cell wall
38
Bacterial genome is ocmposed of
one circular chromosome
39
Chromosomes replicate inside of cell and cell divides by..
binary fission
40
Antibiotics
molecules that kill bacteria
41
Most bacteria produce ___________
asexually
42
_______ protein ring constricts membrane and cell wall infold in bacterial cell division
Fts protein
43
Differences in sex between Eukaryotes and Prokaryotes
No meiosis
| Chromosomes are not brought together
44
Prototrophs
provide basic food source and they take care of the rest
45
Ausotrophs (mutant)
need supplements
46
Bacterial Mutants
```
Affect colony morphology
Confer resistence to antibiotics or phages
creat auxotrophs
affect ability to break down chemicals
mutations in essential genes
```
47
wild type
+
48
bio-
Requires biotin added as a supplement to minimal medium
49
arg-
Requires arginine added as a supplement to minimal medium
50
met-
requires methionine added as a supplement to minimal medium
51
lac-
cannot utilize lactose as a carbon source
52
gal-
cannot utilize galactose as a carbon source
53
str ^r
resistant to antibiotis streptomycin
54
str^s
sensitive to antibiotic streptomycin
55
Conjugation discovered by..
Jashuo Lederberg and Edward Tatum by stidying auxotrophic mutations in two strains
56
Mixing bacterial genotypes produces...
rare recombinants
57
Discovery of the F factor is...
William Hayes
58
F factor donor does or soes not contribute all of its genome
DOES NOT
59
F
plasmid that directs synthesis of pili
60
F+
acts as a donor
61
F-
acts as a receptor
62
Conjugation
physical contact is essential
physical contact occurs via pilus
Pili are synthesized by the F plasmid
63
Hfr discovered by..
Luca Cavalli-Sforza
64
Hfr X F- strains....
produce 1000X more recombinations compared to F+ and F- matings
no conversion from F- to F+
65
Recombination between Hfr transferred genetic material and F- recipient genome =
high frequency of recombinants
66
DNA is transferred as a __________ in bacteria
single strand
67
crossovers integrate ________________
donor fragment
68
Position of F factor in chromosome determines...
the order of gene transfer
69
Homologous regions are segments of transposable elements called...
insertion sequences
70
F' plasmids
can carry a single gene
| or large chunks of bacterial chromosomes
71
R plasmids example:
Shigella
72
R plasmids have been engineered to create tools for.....
recombinant DNA technology
73
Transformation..
another genetic transfer
| genetic material from dead bacteria or bacteria secreting DNA into the medium
74
Virus'
lack own metabolism
Lack cells
Lack ability to self-replicate
75
Viruses infect...
animals and plants
76
Bacteriophages
most widely distributed and diverse entities in the world
77
Bacteriophages can be used two ways for genetic analysis
1) Can bring two phage genotypes in an effort to map the viral genome
2) Can also be used to bring bacterial genes together for analysis
78
Phage T4 consists of
a nucleic acid "chromosome"
79
Two types of bacteriophage life cycles
1) Lytic
| 2) Lysogenic
80
Lytic
Virulent Phages
81
Lysogenic
Temperate Phages
82
Lytis
Phage takes over the host machinery, replicates its genetical material, multiplies, kills the cells releasing new phage particles
83
Lysogenic
phage integrates into the host genome, lies dormant while multiplying
84
A plaque
A clear area in which all bacteria have been lysed by phages
85
plaques are produced by..
Repeated infection and lysis of host cells produces a clear area
86
Plaque Morphology
Come in all forms
| Can be genetically analyzed
87
Host range
analyzed genetically
88
Alfred Hershey..
Phage T2
89
RF =
Sum of recombinants/Total
90
Joshua Lederberg and Norton Zinder
Discovery of transduction
91
Prophage
phage in Lysogenic cycle where phage lies dormant in host
92
Generalized transduction
Phage can carry any part of the host genome
| Demonstrated by Phage P1 and P22
93
Specialized transduction
Phage carries specific parts of the host genome
94
DNA if an F' plasmid is part..
F factor and part bacterial genome
95
Merozygote
Partial diploid
96
Transformation
Free DNA of a different genotype from that of the recipient, the genotype of the recipient can be permanently changed
97
Transduction
Phage sometimes take up host bacterial DNA and transfer it to other hosts in this process
98
A resident temperate phage makes the cell immune to infection of...
A similar phage
99
Cotransduction frequency can give information about..
Linkage of two markers
100
From high co-transduction frequencies, what is inferred?
Close linkage
101
Faulty out looping produces...
Lambda phage containing bacteria
102
Virulent phage
Immediately lose and kill the host
103
Temperate phage
Can remain in the cell for a period without killing it
104
An example of overdoinance
Sickle cell anemia
105
Overdominance
Heterozygous exhibits increased fitness relative to homozygous
106
French biologist demonstrated Mendelssohn law applied to animals
Concluded that 3 genes were responsible for producing 2 enzymes that effect a single phenotype
Discovered lethal null mutations
Lucian cuénot
107
Recessive lethals leads to
Non-Mendelian surviving progeny ratios
108
Pleiotropy
One allele producing multiple effects
109
Most recessive lethals are not
Pleiotropy
...homozygous are dead
....heterozygotes have no phenotype
110
Permissive temperature
Wild type phenotype
111
Restrictive temperature
Mutant phenotype
112
A french biologist
Lucien Cuebnot
113
discovered "lethal" null mutations
Lucien Cuebot
114
Recessive lethals lead to....
non-mendelian surviving progeny ratios
115
Pleiotrophy
Mutations produce mutliple effects
116
Most recessive lethal alleles ______ pleiotrophic
ARE NOT
homozygotes -> dead
heterozygotes -> no phenotype
117
Beadle and Tatum
neurospora experiments
irradiated wild type to generate mutants
118
One gene ______ ________ hypothesis
one enzyme
119
Complementation theory
cross two homozygous mutant lines and score the heterozygous progeny
120
Incomplete penetrance
individuals with identical genotypes may have non-identical phenotypes
121
A trait can be __________ penetrant
incompletely
122
Penetrance
Precentage of individuals have a particular genotype that actually express a particular phenotype
123
Expressivity
The degree to which an allele is expressed
| *brown pigments in bears
