Molecular 18-19

Question 1

Why cant genomes be 100% functional ?

Answer 1

It would require huge Ne and really short generation times

Question 2

What is the C-value a good measure of ?

Answer 2

The haploid genome in bp

Question 3

What are the 3 things that effect genome size ?

Answer 3

Genome duplications
Transposable elements
Deletions

Question 4

What can have a profound effect on the C-value

Answer 4

transposable elements

Question 5

What is literal DNA ?

Answer 5

Functional DNA that the order of nucleotides is constrained

Question 6

What is indifferent DNA ?

Answer 6

Functional DNA but order of nucleotides is not constrained

Question 7

What is garbage DNA ?

Answer 7

DNA that is selected against

Question 8

What is junk DNA ?

Answer 8

DNA that is not useful but doesnt have deleterious effects so isnt selected against.

Question 9

Why does the neutralist theory believe that most of the genome is non functional ?

Answer 9

Because cost of replication is negligible

Question 10

Are large or small genomes more evolutionary successful

Answer 10

small

Question 11

What is the c-value paradox ?

Answer 11

The lack of correlation between genome size and complexity

Question 12

What is the G-value paradox ?

Answer 12

The lack of correlation between the number of protein coding genes and the complexity of an organism

Question 13

Why do apes and humans have a different number of chromosomes ?

Answer 13

telomere-telomere fusion event between 2 ancestor chromosomes

Question 14

What is molecular tinkering ?

Answer 14

A combination and modification of pre-existing functional and non functional genetic elements.

Question 15

What is the protein domain ?

Answer 15

A well defined region in the protein that is stable and independently folding unit with a 3d structure
Has a distinct function

Question 16

How many domains do function proteins have ?

Answer 16

2 or more

Question 17

What does internal duplication cause ?

Answer 17

Tandem repeats

Question 18

Why is internal duplication a particular problem for eukaryotes ?

Answer 18

Introns can replace exons which will effect splicing resulting in the loss of info

Question 19

What causes domain reshuffling ?

Answer 19

When exons correspond to more than one protein domain or when multiple exons correspond to the small domain

Question 20

What does domain reshuffling cause ?

Answer 20

Mosaic chimeric proteins: The gene contains sequences that are found in nonhomologous genes

Question 21

What is gene fission ?

Answer 21

A multidomain gene that is split into 2 or more transcriptional units

Question 22

What is the problem with gene fusion ?

Answer 22

One gene ends up being under control by the other promoter

Question 23

What is domain accretion ?

Answer 23

Domains can be added to existing domains to add complexity and alter function

Question 24

What is exonization and pseudoexonization ?

Answer 24

exonization: introns become exons this is generally deleterious
pseudoexonization: When exons become non functional

Question 25

What does alternative splicing of the primary RNA transcript result in ?

Answer 25

The production of different mRNAs from the same DNA fragment which will be translated into different polypeptides

Question 26

Why can genetic elements alter phenotype ?

Answer 26

They can jump to different places in the genome

Question 27

What is the difference between mobile and transposable elements ?

Answer 27

Mobile elements can be integrated into genomes where as transposable elements can only move intragenomically

Question 28

What type of transposable element has code for reverse transcriptase ?

Answer 28

Retroelements

Question 29

What are retrosequences ?

Answer 29

Accidental retro elements that exhibit no adaptation for retroposition

Question 30

What are retrogenes ? and what can they cause ?

Answer 30

They are functional retrosequences that produce a protein that is identical to the one produced by that gene that the retrogene is derived from.

Question 31

Give 2 examples of retroelements ?

Answer 31

long interspersed repetitive elements (LINEs)-pseudogenes

Short interspersed repetitive elements (SINEs)- do not contain ORF and need help replicating and moving