Genetics Lecture 1

Front 1

Recognize the significant impact of genetic disease on health care:

A disorder with a significant genetic component was found in ____ of the admitted children
These cases accounted for ____ of the hospital’s total charges during that period.

These patients also have a _______ length of stay

Back 1

A disorder with a significant genetic component was found in 71% of the admitted children
These cases accounted for 81% of the hospital’s total charges during that period.

These patients also have a longer length of stay

Front 2

Describe the processes of mitosis and meiosis, their similarities and differences, and the consequences of errors in either:

Stages of Meiosis and n number after each

Back 2

Chromosomes duplicate = 2n
Meiosis 1 = chromosomes separated = 2n
Meiosis 2 = sister chromatids serparated = reduction division = n

Front 3

Describe the processes of mitosis and meiosis, their similarities and differences, and the consequences of errors in either:

Non disjunction in Meiosis 1?

Back 3

End result is two daughter cells that have an extra copy of a chromosome and two daughter cells with no copy of a chromosome.

All cells are abnormal. 50% chance of an extra and 50% chance of no copy

Front 4

Describe the processes of mitosis and meiosis, their similarities and differences, and the consequences of errors in either:

Example of non disjunction in Meiosis 1

Back 4

two cells with extra copy = Klienfelter (XXY)
two cells with no copy = Turner syndrom (XO)

Front 5

Describe the processes of mitosis and meiosis, their similarities and differences, and the consequences of errors in either:

Non disjunction in Meiosis 2?

Back 5

two normal cells
one cell with extra copy of chromosome
one cell with no copy of chromosome

50% chance of normal, 25% chance of extra, 25% chance of none

Front 6

Summarize the roles of different parts of genes:

Promotor

Back 6

initiates transcription

Front 7

Summarize the roles of different parts of genes.

intron

Back 7

spliced out = non-coding

Front 8

Summarize the roles of different parts of genes.

exon

Back 8

translated region

Front 9

Summarize the roles of different parts of genes.

intron-exon junction

Back 9

location used to combine exons for translation; can be different combinations from the same transcript

Front 10

Summarize the roles of different parts of genes.

3'-UTR

Back 10

section of mRNA that immediately follows the stop codon

The 3'-UTR often contains regulatory regions that influence post-transcriptional gene expression.

Front 11

Summarize the roles of different parts of genes.

5'UTR

Back 11

leader sequence = region of an mRNA that is directly upstream from the start codon.

Front 12

Explain Mendelian laws of segregation and of independent assortment; describe these events statistically using the product rule, the sum rule, and the Punnett square:

product rule

Back 12

the likelihood of independent events occurring together is equal to the product of the independent probabilities.

multiply probabilities together (ie chances of having affected child)

Front 13

Explain Mendelian laws of segregation and of independent assortment; describe these events statistically using the product rule, the sum rule, and the Punnett square:

sum rule

Back 13

the probability of two mutually exclusive events is the sum of the individual probabilities.

add probabilities together (i.e chances of having an unaffected child = fraction of heterozygotes + fraction of homozygous recessive)

Front 14

Explain Mendelian laws of segregation and of independent assortment; describe these events statistically using the product rule, the sum rule, and the Punnett square:

law of segregation

Back 14

chromosomes/alleles can segregate into daughter cells in any possible combination. I.e. AA, Aa, or aa

Front 15

Explain Mendelian laws of segregation and of independent assortment; describe these events statistically using the product rule, the sum rule, and the Punnett square:

law of independent assortment

Back 15

any two genes are inherited as independent units

aka genes aren't linked

Front 16

Discuss the epigenetic relationship between chromatin structure and gene expression; outline common modes of regulating chromatin structure, particularly in imprinting:

two primary ways in which chromatin conformations are altered: _____ and _________

Back 16

histone modification and DNA methylation

Front 17

Discuss the epigenetic relationship between chromatin structure and gene expression; outline common modes of regulating chromatin structure, particularly in imprinting:

______ = open conformation
______ = closed conformation

Back 17

acetylation of lysines= open conformation

deacetylation = closed conformation

Front 18

Discuss the epigenetic relationship between chromatin structure and gene expression; outline common modes of regulating chromatin structure, particularly in imprinting:

methylation events always occur on _________ residues of _______ dinucleotides

Back 18

methylation events always occur on cytosine residues of CpG dinucleotides

Front 19

Discuss the epigenetic relationship between chromatin structure and gene expression; outline common modes of regulating chromatin structure, particularly in imprinting:

methylated states are associated with?

Back 19

methylation of promoter = closed conformation and gene silencing

Front 20

Discuss the epigenetic relationship between chromatin structure and gene expression; outline common modes of regulating chromatin structure, particularly in imprinting:

methylation marks on promoters are _______ during gametogenesis, thereby ________ the epigenetic status of the genome in germ cells

Back 20

methylation marks on promoters are erased during gametogenesis, thereby resetting the epigenetic status of the genome in germ cells

Front 21

Discuss the epigenetic relationship between chromatin structure and gene expression; outline common modes of regulating chromatin structure, particularly in imprinting:

imprinting?

Back 21

methylation patterns that are specific for the parent of origin, a phenomenon known as imprinting

Front 22

Discuss the epigenetic relationship between chromatin structure and gene expression; outline common modes of regulating chromatin structure, particularly in imprinting:

consequence of mutation in some imprinting centers?

Back 22

imprinting centers in essence have only a single functional copy of a gene, so subsequent mutation to the active copy can have deleterious consequences.

Front 23

What is the difference between homologous chromosomes and sister chromatids?

Back 23

homologous chromosomes = same area of genome but from different parents = different copies of same chromosome

sister chromosomes = exact replica of a chromosome

Front 24

Does the law of independent assortment apply to linked genes? What influence does recombination have on the assortment of genes?

Back 24

The law of independent assortment does not apply in the case of linked genes. Recombination is the notable exception as linked genes can be separated by recombinant events. The more tightly the genes are linked, or closer their proximity is, the less the chance they will be split by recombination

Front 25

What is the difference between incomplete dominance and codominance of alleles?

Back 25

Incomplete dominance = phenotype is an "average" or "blending" of parents' phenotype; red + white = pink

Codominance = both are expressed equally; blood types

Front 26

How do heterochromatin and euchromatin differ, both in terms of function and at the molecular level? How are these states influenced by epigenetic modification?

Back 26

heterochromatin = tightly condensed; inactive; dark; AT-rich banding patterns = G-bands.

Euchromatin = less tightly wound; active; appears very lightly stained

Front 27

incomplete penetrance?

possible causes?

Back 27

diseased phenotype is only observed in a fraction of the people with the diseased genotype;

may be due to environment or modifiers

Front 28

pleiotropy?

Back 28

when many systems are adversely affected by a single defect

Front 29

complex traits

Back 29

trait controlled by many genes with possibly very different functions

Front 30

phenocopy?

Back 30

when an environmental factor mimics a genetic condition

example: antipsych meds give you parkinsonian symptoms