Topic 1 Flashcards

(44 cards)

1
Q

what is molecular genetics?

A

study of DNA and RNA structure, function, and molecular control of gene expression

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2
Q

what is evolutionary/population genetics?

A

interaction of genes and gene pools and the environment

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3
Q

what is classical genetics?

A

Deals with inheritance of traits; “Transmission genetics”

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4
Q

what is a gene?

A

a hereditary unit of information

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5
Q

what is a gene locus?

A

the position of a gene on the chromosome

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6
Q

what is an allele?

A

one of two (or more) versions of a gene that differs in sequence and exists at the same loci

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7
Q

what is a genotype?

A

the combinations of alleles for any gene

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8
Q

what is a phenotype?

A

the observable characteristics, as determined by the geneotype

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9
Q

what is wildtype?

A

The most prevalent phenotype in a
population under natural conditions

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10
Q

what is a mutant?

A

a deviation to the wild-type phenotype as a result from an allelic change in DNA sequence

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11
Q

what is dominant?

A

The phenotype observed in heterozygous
individuals (i.e. genotype includes both allele variants)

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12
Q

what is recessive?

A

The phenotype observed only in individuals
that are homozygous for the recessive allele variant

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13
Q

what is dominance determined by?

A

a protein produced by each allele

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14
Q

when is a wildtype phenotype produced?

A

when an organism has two copies of the
wild-type allele, or when one copy is sufficient to meet the protein
requirements

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15
Q

what does it mean when a mutant allele is loss of function?

A

significant decrease or complete loss of functional gene product

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16
Q

what does it mean when a mutant allele is gain of function?

A

gene product acquires a new function or expression increased above wild-type activity

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17
Q

how can a mutation be dominant while also being loss of function?

A

Because the wildtype produces protein however it isnt sufficient to meet the protein requirement and the muatation isn’t producing any protein

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18
Q

what is it called when a mutant is loss of function but dominant?

A

dominant negative mutation

19
Q

what does incomplete domiance suggest for molecular basis of dominance?

A

heterozygous individuals display intermediate phenotypes between
either homozygous type

20
Q

what is codominance for molecular basis of dominance?

A

there is detectable expression of both alleles in the heterozygotes

21
Q

what is recessiveness?

A

when a mutation is functionally haplosufficient—> the mutated allele is the recessive allele

22
Q

what does haplosufficient mean?

A

the mutant is recessive when half of the alleles is sufficient to meet the wildtype phenotype requirements

23
Q

what is dominance (complex)?

A

the mutated allele is the dominant allele when a heterozygote is haploinsufficient

24
Q

what does haploinsufficient mean?

A

the mutant allele is dominant because the wildtype allele cannot provide enough product to achieve the wiltype phenotype

25
what does a single letter mean in nomenclature?
denotes mutant phenotype or recessive
26
what does upper case mean in nomenclature?
denotes dominant allele
27
what does lower case mean in nomenclature?
denotes recessive allele
28
what do slashes mean in nomenclature?
indicates alleles for genes are on homologous chromosomes
29
what do semicolons mean in nomenclature
indicate genes on non homologous chromosomes
30
why is nomenclature important?
it conveys the relationship between alleles and chromosomes, between parents and daughters
31
what is equal segregation?
half of gametes carry one member of a gene pair, half carry the other member
32
what is another name for equal segregation?
mendels first law
33
what does non autosomes mean?
sex chromosomes
34
what happens if one sex does not have a pair of similar sex chromosomes?
the other does
35
what does homogametic mean?
matching pair of sex chromosomes (XX)?
36
what is a propositus?
the first member of a family who is identified with the mutant type
36
what does heterogametic mean?
no matching pair of sex chromosomes (XY)
36
what does polymorphisms mean?
carriers are common in population
36
what does rare disease mean?
carriers are not common
37
why do we assume new individuals are introduced when we hear rare disease?
because if the disease was present through out the family it probably would have shown up, someone else coming into family would disrupt cross patterns and give new phenotypes
37
what are the traits of autosomal recessive pedigrees?
1. disease shows up from unaffected parents 2. all children will have it if both parents have it 3. males and females have equal chance of getting it
38
what are the traits of autosomal dominant pedigrees?
1. doesn't skip generations 2. sex doesn't matter, equal probablilty 3. Two affected parents can produce unaffected children, but two unaffected parents can never have affected children
39
what are the traits of X-linked recessive disease?
1. more males than females affected 2. if father is affected none of his offspring will be 3. all males offspring of an affected female will be affected
40
what are the traits of x-linked dominant disease?
1. all daughters of an affected male will be affected 2. only need one copy to be affected 3. an affected female will transmit to male and female equally