We noted you are experiencing viewing problems
-
Check with your IT department that JWPlatform, JWPlayer and Amazon AWS & CloudFront are not being blocked by your network. The relevant domains are *.jwplatform.com, *.jwpsrv.com, *.jwpcdn.com, jwpltx.com, jwpsrv.a.ssl.fastly.net, *.amazonaws.com and *.cloudfront.net. The relevant ports are 80 and 443.
-
Check the following talk links to see which ones work correctly:
Auto Mode
HTTP Progressive Download Send us your results from the above test links at access@hstalks.com and we will contact you with further advice on troubleshooting your viewing problems. -
No luck yet? More tips for troubleshooting viewing issues
-
Contact HST Support access@hstalks.com
-
Please review our troubleshooting guide for tips and advice on resolving your viewing problems.
-
For additional help, please don't hesitate to contact HST support access@hstalks.com
We hope you have enjoyed this limited-length demo
This is a limited length demo talk; you may
login or
review methods of
obtaining more access.
Printable Handouts
Navigable Slide Index
- Introduction
- Fundamental evolutionary processes (1)
- Fundamental evolutionary processes (2)
- Fundamental evolutionary processes (3)
- Moving towards molecules
- Genetic variation
- The models in this lecture
- Conceptual models that explain genetic variation (1)
- Key population concepts
- Key concepts (1)
- Key concepts (2)
- Mutations can be fixed or lost
- Conceptual models that explain genetic variation (2)
- Conceptual models that explain genetic variation (3)
- Conceptual models that explain genetic variation (4)
- Neutral theory of molecular evolution (Kimura 1968) (1)
- Neutral theory of molecular evolution (Kimura 1968) (2)
- Why is the equilibrium rate k = μ?
- Neutral theory: precise expectations when mutation & drift are at equilibrium (1)
- Distribution of fitness effects (DFE) of mutations according to neutral theory
- Neutral theory: precise expectations when mutation & drift are at equilibrium (2)
- DFE of mutations according to Kimura’s neutral theory (1)
- DFE of mutations according to Kimura’s neutral theory (2)
- DFE of mutations according to Kimura’s neutral theory (3)
- Please proceed to part 2
Topics Covered
- Introduction to theories of natural genetic diversity
- Within-species genetic polymorphism
- Between-species genetic divergence
- Fundamental processes of evolution
- Mutation
- Natural selection
- Genetic drift
- Neo-Darwinism
- Neutral model
Links
Series:
Categories:
Talk Citation
Bielawski, J.P. (2022, July 31). The neutral and nearly neutral theories of molecular evolution 1 [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved December 8, 2024, from https://doi.org/10.69645/KYEZ1067.Export Citation (RIS)
Publication History
Financial Disclosures
- Prof. Joseph P. Bielawski has not informed HSTalks of any commercial/financial relationship that it is appropriate to disclose.
The neutral and nearly neutral theories of molecular evolution 1
Published on July 31, 2022
33 min
Other Talks in the Series: Introduction to Evolutionary Biology
Transcript
Please wait while the transcript is being prepared...
0:00
Hello and welcome.
My name is Joseph Blelawski.
I'm an evolutionary biologist.
I'm cross-appointed in the
Department of Biology and
the Department of
Mathematics and Statistics
at Dalhousie
University in Canada.
Today, I'm going to lecture on
an introduction to
and a comparison
of the neutral and
nearly neutral theories
of molecular evolution.
0:24
Before we dive into the
details of those theories,
we need to do a quick review of
the three fundamental
processes of evolution.
They are genetic mutation,
natural selection, and drift.
Here I'm going to
start with mutation.
I've got a picture of the
familiar double helix
of DNA on the screen here,
which is the hereditary
material in humans
and almost all living organisms.
This is an information
storage system.
It's a biochemical
system in a language
that has an alphabet
of just four letters.
Not unlike our language
with 26 letters,
but much more efficient.
The information
stored in the DNA
is determinant of a
heritable phenotype.
I need to be careful here.
I do not mean full
genetic determinism.
It's important to remember
that the environment
can also affect phenotype.
These phenotypic effects
of the environment
are not transmittable
from parent to offspring.
Just a quick example.
Imagine an organism loses
a limb at some point.
It's not going to transmit
that loss of limb
to its offspring.
When we talk about
the genes or the
genetic information being
determinants of phenotype,
we're saying it's the
fraction of total phenotypic
variation that can
be transmitted from
parents to offspring over time.
We talk about the unit
of that transmission of
information between parents
and offspring as a gene,
which brings us to mutation.
Mutations are thought about
in the context of genes,
and they are the
ultimate source of
heritable phenotypic variation
that is subject to
evolution over time.