Lecture 25

Question 1

What is the minimal genome?

Answer 1

The minimal set of essential genes to live independently of the host

Question 2

What does the minimal genome term exclude?

Answer 2

Excludes viruses and obligate intracellular parasites or endosymbionts that cannot be cultured outside of their host

Question 3

What is an essential gene?

Answer 3

A gene essential for growth or survival. If there is a mutation in this gene, there will be no growth

Question 4

Describe conditionally essential genes

Answer 4

They are essential depending on the growth conditions

Question 5

Describe essential but redundant genes

Answer 5

Some genes can do the same essential functions so deletion of the other gene is tolerated

Question 6

Describe P.Ubique’s genome

Answer 6

• No known pseudogenes/unknown function genes. The working genes are tightly packed
• No gene duplication and no evidence of HGT

Question 7

What is the hypothesis around P.Ubique’s genome?

Answer 7

The some niches select for minimised DNA replication costs therefore the genomes are streamlined

Question 8

Describe P.Ubique

Answer 8

• Smallest free-living bacteria
• Grown in the oceans using dissolved organic carbon
• Constitutive slow growth that doesn’t respond to increased nutrient availability

Question 9

What do conserved genes across genomes identify?

Answer 9

They identify and predict essential genes