| Range |
≈0.05 unitless (units uncertain)
|
| Organism |
Bacteria Escherichia coli |
| Reference |
Lenski RE, Travisano M. Dynamics of adaptation and diversification: a 10,000-generation experiment with bacterial populations. Proc Natl Acad Sci U S A. 1994 Jul 19 91(15):6808-14. p.6812 left column 2nd paragraphPubMed ID8041701
|
| Method |
"Twelve
populations
of
E.
coli
B
were
propagated
in
replicate
environments
for
1500
days
(10,000
generations).
Each
population
was
founded
by
a
single
cell
from
an
asexual
clone,
and
so
there
was
initially
no
genetic
variation
either
within
or
between
replicate
populations
(except
for
a
neutral
marker
used
to
identify
populations).
The
experimental
environment
consisted
of
a
serial
transfer
regime,
in
which
populations
were
diluted
(1:100)
each
day
into
10
ml
of
a
glucose-limited
minimal
salts
medium
that
supports
˜5x10^7
cells
per
ml.
Populations
were
maintained
at
37°C
with
aeration.
Every
day,
the
bacteria
underwent
a
lag
phase
prior
to
growth,
followed
by
a
period
of
sustained
growth,
eventual
depletion
of
the
limiting
glucose,
and
starvation
until
the
next
serial
transfer.
The
1:100
dilution
permits
˜6.6
(log2[100])
cell
generations
per
day.
Samples
from
each
population
were
periodically
stored
at
-80°C,
along
with
the
common
ancestor...Fitness is the most important property of any organism
according to evolutionary theory. The mean fitness of
a population was obtained by allowing it to compete against
the common ancestor. Relative fitness was then calculated as
the ratio of the competitors' realized rates of increase (Malthusian
parameters)." |
| Comments |
"After
10,000
generations,
the
among-population
standard
deviation
for
fitness
was
˜0.05,
while
the
average
fitness
gain
from
the
ancestral
state
was
˜0.48." |
| Entered by |
Uri M |
| ID |
110463 |