Module 1 Flashcards
(194 cards)
1
Q
What is Transmission Genetics?
A
- focuses on the individual
- how genes are passed
- meiosis, reproduction, heredity
- genes and phenotype probabilities and the factors that affect it
- proximity affects recombination adn frequency and probability of a gamete being produced
2
Q
What are molecular genetics?
A
- focuses on gene
- structure organization and function of gene
- replication, transcription, translation
consequences of mutations at protein level
3
Q
What is population genetics?
A
- focuses on a group of genes in a population
- Hardy Weinberg
- phylogenic trees
- factors can change genetic composition of pop over time.
4
Q
What are the subdivisions of genetics?
A
- biotech
- population
- molecular
- transmission genetics
5
Q
Do eukaryotes have a nucleus?
A
yes it has a nucleus that has chromosomes
6
Q
What cells are eukaryotes?
A
-plant and animal cells
7
Q
Are prokaryotes or eukaryotes bigger?
A
- eukaryotes
8
Q
What size are eukaryotes?
A
- larger
9
Q
What size are prokaryotes?
A
- smaller
10
Q
What does DNA look like in a eukaryote?
A
- multiple linear DNA molecules
11
Q
Do eukaryotes have a histone?
A
- yes
12
Q
Does a eukaryote have membrane-bound organelles?
A
yes
13
Q
What kind of DNA does prokaryotes have?
A
- 1 circular DNA molecule
14
Q
How much DNA does a prokaryote have?
A
small amount of DNA
15
Q
Do prokaryotes have histones?
A
- no DNA in bacteria
- some DNA in archaea
16
Q
Do prokaryotes have membrane-bound organelles?
A
- no
17
Q
What does every functional chromosome have?
A
- centromere
- telomere
- at least one origin of replicaiton
18
Q
How many centromeres can a chromosome have?
A
more than 1
19
Q
How many chromatids can a chromosome have?
A
1 or 2
20
Q
How can you determine the number of chromosomes from the number of centromeres?
A
they are equal
21
Q
Are all centromeres in the middle?
A
no centromeres can in be in all different locations as long as chromosomes of the same type have the centromere in the same place
22
Q
What are homologous chromosomes?
A
- have same info but slightly different ways of expressing it
23
Q
What is a gene?
A
a unit of genetic material
24
Q
What is an allele?
A
- a version of a gene
- a gene can have 1000s of alleles
25
What is a locus?
- the location in the chromosome where the gene is found
26
What is a karyotype?
- organized array of an individuals chromosome
27
What are autosomes?
same chromosomes and number of homologs between sexes
28
What are sex chromosomes?
- different chromosomes or number of chromosomes between sexes
29
What happens in g1 phase of the cell cycle?
- cell grows and produces proteins
- part of interphase
30
What happens in the s phase of the cell cycle?
- DNA syntheses
- 1 chromatid to two chromatids
31
What happens in the g2 phase of the cell cycle?
cell growth
32
What happens in the mitotic phase of the cell cycle?
- mitosis and cytokinesis
33
What phase of cell division contains g1, s, and g2 of the cell cycle?
interphase
34
What is N?
- the ploidy number
- number of sets of chromosomes
35
What ploidy number are humans?
- 2n
-diploids
- 2n=46
36
What is the total number of chromosomes?
The total number of chromosomes in a somatic cell during g0 or g1
37
What is a haploid?
- bacteria
- 1 of each chromosome
38
What is a diploid?
- 2 of each chromosome type during g0 or g1
39
What is mitosis?
-regeneration of pre-created cells
40
What are the phases of mitosis?
- interphase (kinda)
- prophase
- metaphase
- anaphase
-telophase
- cytokinesis
41
What happens during mitotic prophase?
- chromosomes condense
- nuclear envelope breaks down
- spindles develop
42
- What happens during mitotic metaphase?
- spindle poles form
- checkpoint
- everything lines up in center
43
What are spindle poles made of?
- microtubules
44
What happens during mitotic anaphase?
- chromosomes split into 2 daughter chromatids to form 2 different chromosomes since there is a centromere
45
What happens during mitotic telophase?
- reform nuclear envelope
- spindle rods let go
46
What happens during cytokinesis?
- cell fully breaks down forming 2 daughter cells
47
What is meiosis?
- sex/ gamete cell divides to produce 4 meiotic products with 1/2 of og chromosome number
48
What are the steps to meosis?
1. reductional division
2. equational division
49
What is reductional division?
- number of chromosomes in daughter cell = 1/2 of the cell
- 1 of each homologous pair is in daughter cell
- SEPERATION OF HOMOLOGS
50
What is equational division?
- number of chromosomes at beginning and end of division cycle is the same but daughter cells only have 1 chromatid
- SEPERATION OF CHROMATIDS
51
What is formed by the end of meiosis?
- four individual products
52
What are the phases of meiosis?
- prophase 1
- metaphase 1
- anaphase 1
- telophase 1
- prophase 2
- metaphase 2
- anaphase 2
- telophase 2
53
What happens during meiotic prophase 1?
- homologous chromosomes pair up and synapse
- crossing over/ recombination occurs
- crossing over keeps chromosomes attached
54
What happens during meiotic metaphase 1?
- line up in middle, but homologs are together
55
What happens during meiotic anaphase 1?
homologs seperate
56
What happens during meiotic telophase?
nuclear envelope reforms
57
What happens during meiotic prophase 2?
- DNA condenses
- nuclear envelope breaks down
58
What happens during meiotic metaphase 2?
- 2 chromosomes in each cell (1/2 starting amt)
- chromosomes line up in center
59
What happens during meiotic anaphase 2?
chromosomes split and pull to side
60
What happens during meiotic telophase 2?
- cell starts to divide
- nuclear envelope starts to form
- rods break off
61
What is the importance of meiosis?
- maintains constant number of chromosomes from gen to gen
- provides genetic variability from gen to gen
- helps with ability to adapt
- shuffling of maternal and paternal genes allows for over 8 million gene combos
- crossing over allows for some maternal and some paternal genes
62
How do chromatids stay together and come apart
cohesion and shugoshin
63
What is cohesion?
- holds sister chromatids together in mitosis and miosis
- it also acts as chiasmata in meiosis to hold homologs together
64
Is cohesion the same in meiosis and mitosis?
no, each one has a different form of cohesion
65
What does shugosin do?
- protects cohesion at centromere in anaphase 1 of meiosis
- is degraded by anaphase 2
- allows homologs to separate in anaphase 1 but keeps sister chromatids together
- only in meiosis
66
What is non-disjunction?
- creates gametes with more or less chromosomes than normal
- occurs in meiosis because of cohesion and shigoshin
67
What happens if there is non-disjunction in bigger chromosomes or more than 1 chromosome?
fatal
68
What is down syndrome caused by?
-nondisjunction
- extra 21st chromosome
69
What did Mendel do?
- used math to try and understand how traits are passed from parents to offspring
- studied pea plants to create his laws
70
What is a monohybrid cross?
- one trait
71
What is pure breeding?
- traits look the same generation to generation
- multiple generations of breeding with itself
72
What are the generations in order?
- P: parent generation
-F1: first generation of offspring (PXP)
- F2: second generation of offspring (F1xF1)
73
What did mendels research show the presence of?
dominant and recessive genes
74
What is a dominant gene?
- only need one allele to show the trait
75
What is a recessive trait?
- need two alleles to show the trait
76
What is a genotype?
- the alleles a person has
77
What does homozygous mean?
- two of the same allele
- same thing as pure breeding
78
What does heterozygous mean?
- 1 of each allele
79
What were mendels observations?
- each human has two alleles
- hereditary determinants are distinguished units moving into offspring
- 1 unit is dominant and the other is recessive
- during fertilization particles separate random and equally so that each gamete contains one pair of alleles
- fertilization is random
80
What is the law of segregation?
- 2 alleles on a locus don't blend of fuse, but segregate randomly into the gametes so that 1/2 of the gametes contain 1 allele and 1/2 contain the other
- if you are heterozygous 1/2 is R gene and 1/2 is r gene
81
What do you do to test if someone is heterozygous or homozygous?
- preform a cross test
- if homozygous there is one offspring outcome
- if heterozygous there is 3 offspring outcomes
82
What is a dihybrid cross?
- 2 traits
83
1 heterozygous dihybrid can make how many different gametes?
4
84
What ratio does a dihybrid cross create?
9:3:3:1
85
What is the law of independent assortment?
- segregation of alleles at one locus is independent of the segregation of alleles at all the other loci
- basically genes don't influence each other
86
What is the multiplication rule?
- if 2 events occur independently, the probability of them occurring simultaneously is the product of the probabilities occurring by itself
- more common rule
- think of dice landing on 6 and coin landing on heads at same time
87
What is the addition rule?
- the probability of 2+ mutually exclusive events is the sum of the probabilities
- this OR that
- rolling a 2 or rolling a 6
88
How do you determine the number of gamete possibilities?
- 2^n
- where N is the number of HETEROZYGOUS loci
89
What does chi square determine?
- how well observed data fits unexpected results from a genetic hypothesis
- goodness of fit
90
What is Ho?
-your hypothesis
- the mode of inheritance for x and y in x species is simple mendelian
91
What are the rules for mendelian inheritance?
- 1 allele is completely dominant unless hypothesis says otherwise
- random segregation occurs at all loci involved in the test
- independent assortment occurs at all loci involved in the test
- random fertilization occurred in producing the individuals in the generation that is being tested
92
How do you determine the expected value for chi-square?
- ratio of the possibility x the number of test subjects
93
How do you determine the observed value for chi- square?
its given
94
How do you determine the DOF for chi- square?
- # classes- 1
95
What does it mean if the calculated chi-square value is greater than the critical value?
- data is not consistent with hypothesis
- reject hypothesis
96
What does it mean if the calculated chi-square value is less than the critical value?
- data is consistent with hypothesis
- fail to reject hypothesis
97
What is the chi-square formula?
x^2 = (observed-expected)^2 / expected
98
How does environment determine sex?
- temp where egg is incubated
- proteins in sex determination pathways function differently based on temps
99
What's an example of how environment determines sex?
- aromatase (testosterone to estrogen) activity is low at male temps and higher at female temps
- warm= female
100
How does climate change affect genetics?
- warmer = more female sea turtles
101
What is haplodiploid?
- where males are haploids (unfertilized egg) and females are diploids
- females must be heterozygous for a single multiple allele locus
- means females can reproduce males on their own
102
What type of sex determination do insects have?
haplodiplidy
103
What is the xo/xx protenor sex chromosomes
1 = xx 1= x_
- sexes have different number of chromosomes
- ex = grasshoppers
104
What are the xx/xy lygaeus mode chromosomes?
- same number of chromosomes but one isn't homologous
- fruit flies and mammals
105
What are homogametic organisms?
- all gametes have the same chromosomes. (doesn't mean same alleles)
XX
106
What are heterogametic organisms?
- different chromosome types
- xy
107
What are homogametic organisms?
- if you only have one allele to pass down
- dads only pass x to daughters
108
Why are some diseases more prevalent in XY?
- because only 1 x so no masking, dads only pass down y
109
What are zz/zw chromosomes?
- zw = female
- zz = male, homogametic
- ex = birds, butterflies, some fish and amphibians
110
What are pseudoautosomal regions?
- regions of homology between x and y can allow for crossing over but no long exchange of info
111
Where would you see pseudoatuosomal regions?
-during prophase 1 where x and y pair up
112
What is the SRY gene?
- codes for testes determination factor (TDF) which triggers undifferentiated gonadal tissue to form tissue
113
What happens if there is no SRY present?
- ovaries develop
114
Where is non-disjunction the most common in humans?
sex chromosomes
115
What are the types of non-disjunction in sex chromosomes?
- XO
- XXY
- XXX
- xyy
116
What is a XO chromosome non-disjunction?
- turner syndrome
- no secondary female characteristics
- 45 chromosomes
117
What is the XXY chromosome non-disjunction?
- klinefeller syndrom
- male that has female secondary sex characteristics
- 47 chromosomes
118
What are the XXX and XYY chromosome non-disjunctions?
- no phenotypic consequences until you go to reproduce
- this is because Y doesn't do much and the extra x can be turned off
119
What is the Lyon hypothesis for dosage compensation?
- inactivation of an x chromosome occurs randomly in somatic cells at some point in development.
- once inactivated all progeny have the same X inactivated
120
What is a Barr body?
- inactivated X
- not completely shut off (like 90% off)
121
How many Barr bodies does the avg female have?
1
122
How many Barr bodies does the avg male have?
0
123
How many Barr bodies does someone with turner syndrome have?
0
124
How many Barr bodies does someone with Klinefelter syndrome have?
1
125
How do you test for x-linked genes?
- reciprocal cross
126
What is a reciprocal cross look like?
- females always look the same in both variations but males always look like mom
127
Do dad's give an X to their sons?
no
128
Is there a difference in an autosomal traits reciprocal cross?
- no because reciprocal crosses only show sex- linked characteristics
129
What do genetic counselors do?
- work with parents concerned about inherited conditions
130
What are the types of genetic counselors?
- prenatal
- pediatric
- adult onset
- cancer
131
What do genetic counselors talk about?
- diagnosis/ genetics/ inheritance abt disorder
- symptoms and treatment options
- risks and likelihood of having another child with disorder
- social and psychological aspects of managing the disorder
- assisting with finding support groups
- typically non-directive
132
What are prenatal genetic testing options?
- ultrasound
- fetal cell sampling diagnosis
- preimplantation genetic diagnosis
133
When is an ultrasound for genetic testing done?
20 weeks
134
When is a maternal blood fetal protein DNA screening done?
10 weeks
135
What is maternal blood fetal protein/ DNA screening?
- buildup of proteins that are markers for abnormalities
- cell/ free fetal DNA high throughout sequencing of fetal DNA fragments in moms blood
136
Is a maternal blood fetal protein/ DNA screening diagnostic?
no
137
What are the types of fetal cell sampling diagnosis techniques?
- amniocentesis
- chromic villus sampling
138
When is amniocentesis preformed?
weeks 13-18
139
When is chronic villus sampling done?
week 6
140
What is amniocentesis?
- more invasive
- takes amniotic fluid
141
What is chronic villus sampling?
takes cells from fetal part of placenta
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When would preimplantation genetic diagnosis be done?
- in conjunciton with IVF
143
When is most infantile genetic screening done?
- during the newborn heel prick
144
What are the types of genetic testing?
- diagnostic testing
- predictive and pre-symptomatic genetic testing
- carrier testing
- pharmocogenetic testing
- research genetics
145
What is diagnostic genetic testing?
- identifies genetic condition or disease that is making or in the future will make a person ill
- results can help with treatment and management
146
What is predictive/ pre-symptomatic genetic testing?
- finds genetic variations that increase a persons chance of developing a certain disease
147
What is carrier genetic testing?
- if people carry a gene that cause a disease
148
Do carriers show any symptoms of the disease they could give to their child?
- no
149
What is pharmocogenetic testing and the use?
- give info on how certain medicines are processed in a person's body
- gives info on what meds would work best to treat something
150
What is research genetic testing?
- tells scientists how genes contribute to health and disease as well as develop gene-based treatments
- doesn't always help participants but benefits future people
151
What is the genetic information non-discrimation act?
- health insurance companies can't decrease coverage or increase rates based on genetics test
- employers can't discriminate bc of genetic tests
- employers and insurance can't require genetic testing
152
What does a square mean on a pedigree?
male
153
What does a circle mean on a pedigree?
female
154
What does a triangle line mean on a pedigree?
dizygotic twins
155
What does a tringle line with another line mean on a pedigree?
monozygotic twins
156
What are most simple mendelian traits?
- diseases
- not traits like eye color or earlobes
156
What is complete dominance?
- one allelic form is expressed (dominant) and one isn't seen (recessive)
157
what does a double line or a star mean on a pedigree?
incest
158
What is incomplete dominance?
- intermediate to parents
- purple + white= light purple
- ONLY ONE GENE PRODUCT PRODUCED
- varying amounts of the gene create the phenotype
159
What is the incomplete dominance ratio?
- 1:2:1
160
What is codominance?
- heterozygote expresses both alleles as distinct gene products
- 2 functional genotypes
161
What is the codominance ratio?
- 1:2:1
162
What is a recessive lethal?
- animals with 2 copies of x die
- can be dominant for a different trait and recessive for dealth
163
What is a dominant lethal trait?
- deadly if only one copy of the allele
- makes it difficult to observe, only see if they don't die before birth
164
What is huntingtons?
- recessive dominant
- extra copies of CAG gene
- shows anticipation
165
What is anticipation?
- increasing severity or earlier age of onset as the trait passes from generation to generation
- individuals show symptoms earlier and progresses quicker
- repeat grows more severe
166
How do multiple alleles work?
- more than 2 forms of same gene, each may be capable of producing a different phenotype
- a diploid organism has 2 alleles at any locus, but may be many alleles in the population
167
What is an allele series?
- W>X>Y>Z
- w dominant to everything
- Y is dominant to z but recessive to x and w
168
What type of trait is blood?
- codominance
169
What is penetrance?
- percent of individuals of a given genotype that show some degree of expression of gene
170
What is expressivity?
- range of expression of a genotype
- no numbers involved
- just because you have the phenotype doesn't mean you show it
- ex. polydacty
171
What factors influence a phenotype of a genotype?
- modifying genes
- imprinting
- environmental (temp, nutrition, light)
172
What are pleiotropic effects?
- 1 gene has an effect on several seemingly unrelated aspects of someone's phenotype
- 1 gene affects the phenotype of several unrelated traits
173
How does epistasis happen?
- each gene specifies a different polypeptide product, these peptides determine the organism's phenotype
- different genotypes can lead to the same phenotype
- it's the interaction between 2 different genes (not between the alleles at one locus)
174
Which gene is the epistatic gene?
- gene doing the masking of the other
175
What is single recessive epistasis?
- homozygous recessive condition at one locus that masks or modifies the expression of alleles at the second location
- aa creates white no matter what B is, if A we have to look at b
176
What is single dominant epistasis?
- if A is epistatic to be then A_ creates a result no matter what B is
- a protein would be an inhibitor in this case and serves as a repressor that prevents conversion of precursor to intermediate
177
What is a duplicate recessive epistasis?
- identical phenotypes are produced by homozygous recessive so a different phenotype is only produced if there is at least 1 dominant of each locus
- aa__ and __bb result in same phenotype no matter the genotype of the other locus
178
What is duplicate dominant epistasis?
- a dominant allele at either location gives us the same result
179
What is dominant/recessive epistasis?
- dominant at one locus and or homozygous recessive at the other locus results in the same phenotype
- A__ and aabb result in same phenotype
180
What is the difference between epistasis and dominance?
- epistasis is the interaction between products of different genes
- dominance is the interaction between different alleles at a particular gene
181
What are complementation tests?
- tests if two mutations are alleles of the same gene
- want to cross to strains
- mutations in same gene complementation doesn't occur, mutations are alleles of the same locus and creates mutant phenotype
- mutations in different genes complementation occurs and mutations aren't alleles, creates proper phenotype
182
What is a sex limited trait?
- autosomal charecteristic that is only expressed in 1 sex or the other
183
What is a sex influenced trait?
- an autosomal trait that can be expressed in either sex but more fluent in one sex than the other
- recessive in one gender but dominant in the other
184
What is genetic maternal effect?
- phenotype of offspring is determined by genotype of mother, not its own genotype
- doesn't impact dan only looks
185
What is extranuclear/ cytoplasmic inheritance?
- genes in mitochondria or chloroplast DNA and generally are passed down from only mother
- does impact DNA
186
What are characteristics of cytoplasmic traits?
- only when eggs are laid externally
- effects males and females
- passed from mom to all offspring
- reciprocal crosses give different traits
- shows extensive phenotypic variation even within a family
187
What are examples of extracellular DNA inherited through cytoplasmic organelles?
- chloroplasts and photosynthesis
= mitochondria and aerobic respiration
188
What causes mitochondria diseases?
- defects in bioenergetic function of cell
189
What causes mitochondrial disorders variation?
- 2 types of mitochondria in OG cell, mitochondria replicates then cell
- by chance some daughter cells can end up with mostly defective mitochondrial DNA while others can end up with mostly normal mitochondria, varying scale
190
What is the endosymbiotic theory for organelle origin?
- based on observation that mitochondria and chloroplast DNA and the apparatus associated with their DNA function is similar to that of bacteria
- many antibiotic resistance genes found in bacteria have been seen in DNA of mitochondria and chloroplasts
- possible origin of organelles is that they were distinct bacteria-like organisms that became incorporated into primitive eukaryotic cells
- symbiotic relationship developed through evolution so that each became dependant on others to survive
191
What is genomic imprinting?
expression of a gene depends on whether its inherited from maternal or paternal side
- often one allele is expressed more highly than the other
- highly variable across tissues and throughout development
- many genes imprinted in clusters
- same genotype different phenotype based of imprinting
192
What are epigenetic?
- heritable changes in gene expression without changes in DNA
- genetic imprinting is one form
193
