lecture 22 - human genome

Question 1

What were the aims of the 1990 human genome project?

Answer 1

Identify all human genes and their roles, and analyse genetic variation between humans and other species.

Question 2

How many base pairs are found in nuclear DNA?

Answer 2

6 billion

Question 3

How many genes are found in the human genome?

Answer 3

Approximately 20,000

Question 4

What is the structure of mitochondrial DNA?

Answer 4

Single stranded, circular

Question 5

How many base pairs are found in mitochondrial DNA?

Answer 5

approx. 16500

Question 6

Where is mitochondrial DNA inherited from?

Answer 6

The mother exclusively

Question 7

How many genes are found on mitochondrial DNA?

Answer 7

37

Question 8

What percentage of genes code for proteins?

Answer 8

<2%

Question 9

What percentage of genes are coding (exons)?

Answer 9

<2%

Question 10

What percentage of the DNA sequence is introns (non-coding segments)?

Answer 10

20%

Question 11

What percentage of the human genome has unknown function?

Answer 11

20%

Question 12

What does SNPs stand for?

Answer 12

Single Nucleotide Polymorphisms.

Question 13

What are SNPs?

Answer 13

Nucleotide sites that commonly vary within populations.

Question 14

What distinguishes an SNP from a mutation?

Answer 14

If a particular combination has more than 1% prevalence in the population, it is considered at SNP.

Question 15

What is the prevalence of SNPs in the human genome?

Answer 15

1 in 300 base pairs.

Question 16

Where do SNPs mainly originate from?

Answer 16

Inheritance from parents, as opposed to just mutation.

Question 17

What is a linked SNP?

Answer 17

An SNP that is outside a gene, and has no effect on protein production or function.

Question 18

What are causative SNPs?

Answer 18

SNPs found in a gene.

Question 19

What are non-coding SNPs?

Answer 19

causative SNPs of a gene that change the amount of proteins produced.

Question 20

What are coding SNPs?

Answer 20

Causative SNPs that change amino acid sequence, and therefore the protein coded for by the gene.

Question 21

Why is there greatest genetic variation in the African Continent, compared to the rest of the world?

Answer 21

The rest of the world’s populations evolved from a bottle-neck population that migrated from Africa - the ‘founder effect.’

Question 22

What does STRs stand for?

Answer 22

Short Tandem Repeats

Question 23

What are STR?

Answer 23

repeats of 2-5 nucleotides, found in specific regions of the genome. In each allele, there are many different possible numbers of repeats possible. You may inherit an allele with a different number from each parent.

Question 24

What are InDels?

Answer 24

Small insertions or deletions in DNA that can cause ‘frame shift’ which changes the way DNA is read in protein coding regions.

Question 25

What does CNVs stand for?

Answer 25

copy number variations

Question 26

What are CNVs?

Answer 26

Chunks of DNA greater than 500 base pairs long that are present at different amounts or ‘copy numbers’ relative to a reference
genome. (More or fewer of a certain type of segment).

Question 27

How many CNVs do humans have?

Answer 27

10,000 within and between genes.

Question 28

Are CNVs exclusive to single genes?

Answer 28

No - they can span multiple genes.

Question 29

The human genome project showed that what percentage of genes code for proteins?

Answer 29

Less than 2%