Telomeres, Mitosis, and Cancer. For life to exist, the information (genes) must be passed on.
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Transcript of Telomeres, Mitosis, and Cancer. For life to exist, the information (genes) must be passed on.
Telomeres are non-gene DNA at the ends of DNA strands.
Telomeres are shortened during DNA replication, and also by DNA damage.
Telomeres are non-gene DNA at the ends of DNA strands.
Short telomeres will cause cells to stop replicating or cell death.
The critical size is unknown.
Telomeres are non-gene DNA at the ends of DNA strands.
Telomeres are shortened during DNA replication, and by DNA damage.
Short telomeres will cause cell senescence or cell death.Telomere size is a measure of mutations.
Do telomere dynamics link lifestyleand lifespan?
Pat Monaghan and Mark F. HaussmannTRENDS in Ecology and Evolution
Vol 21 pg 47
Telomere length varies in different parts of adults:
telomeres - mitosisstomach &blood cells....short - often
Telomere length varies in different parts of adults:
telomeres - mitosisstomach &blood cells....short - often
muscle &brain……….long - rare
Telomere length varies in different parts of adults:
telomeres - mitosisstomach &blood cells....short - often
muscle &brain……….long - rare
liver &kidney……..short - rare
Telomere length varies in different parts of adults:
telomeres - mitosisstomach &blood cells....short - often
muscle &brain……….long - rare
liver &kidney……..short - rare
gametes……long
Telomeres are non-gene DNA at the ends of DNA strands.
Telomeres are more sensitive DNA damage, and may act as a sensor for overall DNA damage level in a cell.
Zebra finch
Telomere length in red blood cells of different birds
Fig. 1 TRENDS in Ecology and Evolution Vol 21 pg 47
Age (years)
common tern
Telomere length in red blood cells of different birds
Fig. 1 TRENDS in Ecology and Evolution Vol 21 pg 47
Age (years)
albatross
TRENDS in Ecology and Evolution Vol 21 pg 47
Telomere length in red blood cells of different birds
Leach’s storm petrel
Telomere length in red blood cells of different birds
Fig. 1 TRENDS in Ecology and Evolution Vol 21 pg 47
Zebra finch
Leach’s storm petrel
common tern
albatross
Telomere length in red blood cells of different birds, different species have different patterns of telomere length and age
Fig. 1 TRENDS in Ecology and Evolution Vol 21 pg 47
Fig. 2 TRENDS in Ecology and Evolution Vol 21 pg 47
Telomere length in white blood cells of different aged people. Telomere length
generally declines, but there is wide variability
THE LANCET • Vol 361 • pg 393
Telomere length and mortality in people over 60 years old
upper 50% of telomere length
lower 50% of telomere length
prop
orti
on s
urvi
ving
%
years after initial assessment
For life to exist, the information (genes) must be passed on.
{Mitosis:producing more cells}
{Meiosis:producing gametes}
Mitosis plays a role in:• Growth and Development
• Repair and Turnover of Cells
• Reproduction
–Asexual
Cell division is regulated by bothpositive and negative signals.
Positive signals start the processof cell division.
Negative signals inhibit cell division.
Cancer:
• is the loss of control over cell division.
• Tumors are normal cells that are dividing inappropriately.
– They stop performing their “normal” function, and are dividing repeatedly.
Causes of mutations:
• Replication errors– Exacerbated by poor DNA repair
• Genetic predispositions for poor repair or already having some mutations
– Limited by telomere length
Causes of mutations:
• Replication errors– Exacerbated by poor DNA repair– Limited by telomere length
• Other biological agents– Viruses– Transposons
Causes of mutations:
• Replication errors– Exacerbated by poor DNA repair– Limited by telomere length
• Other biological agents– Viruses– Transposons
• Environmental factors– Ultraviolet light– Mutagenic chemicals
• smoking, industrial waste, natural toxins