Block C

Question 1

What is a locus?

Answer 1

where on a chromosome a specific gene is found
Plural loci

Question 2

What is Polymorphism?

Answer 2

an allelic form of sequence found in at least 1-2% of the population

Question 3

Polymorphism vs mutation

Answer 3

below 1-2% = rare vaiant/mutation
above probably passed down through generations

Question 4

What are the different types of polymorphic (mutant) DNA sequences? (4)

Answer 4

1. SNP - single-nucleotide polymorphisms
2. Microsatellites: short tandem repeats (2-7 bp)
3. Minisatellites: variable number tandem repeats (>50bp)
4. CNV: copy number variant: 0, 1, 3 or more copies of a large stretch of DNA sequence (1000bp (1kb) > Mb)

Question 5

WHat is an allele?

Answer 5

Specific DNA sequance present at any given locus
(there are 2 copies of each chromosome/locus so 3 different genotypes AA Aa aa)

Question 7

What are the two types of repetitive DNA?

Answer 7

1. Highly repetitive DNA
2. Middle repetitive DNA

Question 8

Highly repetitive DNA what and where?

Answer 8

Satellite DNA - found in long tandem (end to end) strings or arrays
Near telomeres and around centromeres

Question 9

Highly repetitive DNA example

Answer 9

α-satellite DNA (alphoid)
- in centromeres - repeat = millions bp - smaller repeating units contained within repeats

Question 10

2 types of middle repetitive DNA?

Answer 10

1. Mobile DNA elements
   -Transposons = DNA based
   - Retrotransposons = RNA intermediate

2.tandem repeats
- microsatellites
- minisatellites

Question 11

(Retro)transposons consequences?

Answer 11

Look at later slide 15

Question 12

What are microsatellites?

Answer 12

Short tandem repeats (strs)
Single sequence repeats (ssrs)
- tandem repeats of 2-7 nt

Question 13

What are minisatellites?

Answer 13

Variable number tandem repeats (vntrs)
Repeat = 8-100 bp
Tandem arrays up to 40 kbp

Question 14

The satellites-extra

Answer 14

Many show polymorphic variation in repeat numbers so variable lengths.
All through genome (even exons)
Different people have different no. Of repeats

Question 15

What are (rflps) And restriction enzymes?

Answer 15

Restriction fragment length polymorphisms
- sizes are altered by changes in or between enzyme recognition sites

Restriction enzymes=bacterial enzymes that act as primitive immune system
-cuts aspecific phage DNA sequence
- used as a molecular tool inlabs