+ Further Model Organisms

Question 1

Features of aging in NMRs

Answer 1

• Longest lived rodent
• Don’t display increased mortality with age -> Disobey Gompertz laws
• Maintain several physiological functions until nearly the end of their lifetime
• Rarely develop cancer or AD

Question 2

NMR environmentand social structure:

Features relevant to aging theories

Answer 2

• Live in a hypoxic environment -> Relevance to FRT
• Underground -> not subject to UV insults
• Highly tolerant of hypoxia as well as hypercapnia (tolerant to high levels of CO2)
• Inhabits underground tunnels that can get to Kms long in East of African savannahs, feeding on underground tubers
• Eusocial structure similar to that of ant and bees
• Resistant to certain types of pain
• Non-model organism
• Sexual maturation is supressed in subordinate individuals in colonies (majority); this occurs via physical contact to the queen

Question 3

Reminder: Trade-off theory

Answer 3

• In general, energy investment in body maintenance and a low metabolic rate are the main proposed factors for longevity in animals
• There is a trade-off between reproduction in early-life and somatic maintenance in later life
• Investment in somatic maintenance rather than early reproduction can be achieved in species with low risk of extrinsic mortality that are expected to have sufficient breeding opportunities later in life

Question 4

Trade-off theory in relation to NMRs:

Answer 4

• Their unique social structure may support energetic investment in somatic investment due to the inhibition of of early reproduction in most members
• Low extrinsic mortality in underground setting
• Display heterothermic and hypothermic traits
• Highly tolerant to inbreeding -> less dispersal -> likely to stay in safe and tolerable locations

Question 5

Ecological explanations for longevity in NMRs:

Answer 5

• Unique social structure-> reproductive nuances, division of labour
• Subterranean lifestyle -> lack of predation, lack of oxygen, heat regulation
• Mutually synergistic effects arising from harsh habitat

Question 6

Metabolism and signalling in NMRs:

Answer 6

• Hypoxia tolerance -> low metabolic rate and body temp.
• Likely contributing to longevity
• Appear to have decreased thyroid and insulin signalling

Question 7

Biochemical features of NMR aging:

Answer 7

• High DNA repair capacity
• Genome/epigenome features
• Cell death/senescence regulation
• Attenuated inflammation
• Unique oxidative stress response
• High proteostasis
• -> Delayed aging and resistance to age related diseases

Question 8

Genome and RNA sequencing of NMR: Insights into candidate genes regarding evolution of longevity

Answer 8

• Genes associated with oxidoreduction and mitochondria are expressed at higher levels in NMR