Organelle Genomes & Transfer

Question 1

Organelles have a low _ count but a huge _ count

Answer 1

DNA

proteome

Question 2

NORGs are…

Answer 2

integrants of organellar DNA

Question 3

There are approximately _ NUMTs in the human genome and can cause _ by insertion

Answer 3

800

disease

Question 4

What is the mechanism of EGT?

Answer 4

1. organelle lysis

2. integration via non-homologous recomb. into AT-rich or open chromatin sites

Question 5

The majority of EGTs are _ requiring the acquisition of multiple _ factors

Answer 5

non-functional

transcription

Question 6

How do organllar genes acquire Tc-Factors?

Answer 6

De novo - via mutation
Insertion into ORFs
Co-expression via alternative splicing

Question 7

EGT from the organelle to the nucleus if _, the vice versa is _

Answer 7

frequent

rare

Question 8

What is “the ratchet” as it relates to EGT?

Answer 8

Intact, inserted genes will rarely be expressed and may be downstream of an targetting sequence.
Once a gene is lost from the organellar genome its lost forever therefore the nuclear genome will incorporate all available organellar genes eventually

Question 9

Monoplastidic species have the greatest frequency of EGT. T/F?

Answer 9

false, polyplastidic species have nearly 80x more EGT than monoplastidics

Question 10

How does the limited transfer window hypothesis explain the persistence of nucleomorphs?

Answer 10

There is zero detection of EGT in nucleomorph species

Question 11

Why do organelles retain some of their genomes?

Answer 11

1. Hydrophobicity hypothesis - better to retain the coding of hydrophobic proteins in the organelle
2. Redox regulation - expression of key metabolic proteins and complexes (i.e. ETC)
3. Genetic code disparity