Lecture 2 - Components Of Higher Eukaryotic Genomes Flashcards

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1
Q

Does Genome size correlate with complexity of species?

A

No

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2
Q

What is the C value paradox?

A

The idea that bigger genome = more complex organ but this is not true

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3
Q

Does the number of gene significantly increase with the size of genomes?

A

No

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4
Q

Does most of the genome encode protein?

A

No

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5
Q

What do CoT renaturation curves measure?

A

DNA reassociation kinetics measuring the rate by which heat denatured DNA will renature in a solution

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6
Q

In CoT renaturation will all heat-denatured DNA re-associate?

A

Yes

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7
Q

CoT renaturation - what is the rate at which DNA sequences re-associate proportional to?

A

The number of copies of the sequence found in the genome

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8
Q

What does CoT value depend on?

A

DNA concentration, Rex association temperature, cation concentration and viscosity

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9
Q

What is the CoT equation?

A

Co x t x buffer factor

Co - initial concentration of DNA (mol/L)
t - renaturation time (sec)
buffer factor - the effects of cations and the speed of renaturation

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10
Q

What would renature at a lower CoT factor - a single copy sequence or a repetitive DNA sequence?

A

Repetitive DNA sequences

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11
Q

How much of the genome is receptive DNA?

A

70%

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12
Q

What is the encyclopaedia of DNA elements?

A

ENCODE

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13
Q

What is the genome made up of?

A

1.5% - protein coding
26% - non-coding introns
The rest is competitive sequences

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14
Q

What are transcribed in RNA?

A

Exons and introns

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15
Q

What are spliced out to get mature RNA?

A

Introns

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16
Q

What are promotor regions rich in and what do they have?

A

GC rich and CPG island

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17
Q

Where are genes more concentrated about?

A

In GC region

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18
Q

What reveals the distribution of CPG islands?

A

FISH

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19
Q

What side are CPG islands found on?

A

Left side

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20
Q

Are centromere GC poor?

A

Yes

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21
Q

Do all chromosomes have the same GC content?

A

No

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22
Q

What are CPG islands?

A

Short stretches of palindromic DNA that encodes the same sequence in the complementary strand.

23
Q

What are repetitve sequences?

A

Sequence present more than one coy per haploid genome

24
Q

What are the 3 different types of repeats?

A

Gene families - arise from fixed segmental duplications
Interspersed repeats
Tandem repeats

25
Q

After being fixed and duplication genes with go through different fates - one of these is pseudogenization. What is this?

A

The duplication gene is made inactive and is invisible to natural selection

26
Q

After being fixed and duplicated genes will go through different fates - one of these is neofunctionslization. What is this?

A

A new function is evolved

27
Q

After being fixed and duplicated genes will go through different fates - one of these is subfunctionalization. What is this?

A

A duplication occurs in the regulatory elements of the gene which means that two genes need to function together and are independent in one another.

28
Q

What is an example of a gene family?

A

Haemoglobin cluster - these have different forms in fetuses

29
Q

Another example of a gene family amplify signals by making lots of duplicated repeated units. What is this family?

A

His tones

30
Q

In his tones where are his tone gene clusters found?

A

At 4 discrete lock

31
Q

What are interspersed repeats.

A

Dispersed throughout the genome

32
Q

What are the two type of interspersed repeats?

A

LINES and SINE’s

33
Q

Where are SINE’s found?

A

Within and between genes

34
Q

What can be used as markets of SINE’s

A

Alu repeats

35
Q

What have SINE’s and LINE’s integrated using?

A

Reverse transcriptase

36
Q

How do SINEs and LINEs enter the genome?

A

Transcribed into RNA then reverse transcribed into DNA before entering genome

37
Q

What incomes reverse transcriptase?

A

Active LINE

38
Q

Are interspersed repeats commonly suppressed? And why is this good?

A

Repeats can come from anywhere and insert anywhere which is why it’s good they are commonly suppressed

39
Q

In what situation and why would interspersed repeats he dangerous?

A

If they insert into coding regions they can disrupt function

40
Q

Can interspersed repeats cause genome rearrangements?

A

Yes

41
Q

What disease does three line insertions into chromosomes 22 cause?

A

Severe haemophilia A

42
Q

What are variable tandem repeats?

A

Repeats which are dispersed throughout the genome and repeated in tandem

43
Q

What are the three types of satellites?

A

satellite
Minisatellite
Microsatellite (TTAGGG)

44
Q

What are VNTRs variable in number?

A

Unequal crossing over - when recombined they might duplicate or delete

DNA replication slippage - backwards = dna falls backwards and insertion happens
Forward = lagging strand jumps causing deletion

DNA repair adds the tandem repeats

45
Q

Is repeat number inherited?

A

Yes

46
Q

Are repeat numbers stable?

A

No

47
Q

What can unstable repeat numbers cause?

A

Triplet numbers vary and can cause disease

48
Q

How can Microsatellite VNTR’s get worse with each generation inherited?

A

Someone will pass on mutated VNTRS and then their offspring could also have their own VNTRs meaning the offspring have more than the parents did and will get the dues ease earlier than the parents will

49
Q

What are minisatelites?

A

Small sequences of dna that don’t encode protein and appear throughout the genome hundreds of times

50
Q

Are the number of repeats reliably inherited?

A

Yes

51
Q

How does dna fingerprinting work?

A

Digest dna into small fragments using restriction enzymes and run the fragments with minisatelites on a gel.

Southern blot them and then incubate with radioactive dna proves or fluorescence to get a fingerprint

52
Q

Can you amplify minisatelites?

A

Yes but it’s hard as you need to design primers right down the region

53
Q

How can you get a fingerprint from a small region of dna minisatelites in evidence?

A

PCR amplification then separate using gel electrophoresis and then create histograms to compare size of fragments

Currently they use short tandem repeats (STR’s)