Class Notes (811,155)
Canada (494,530)
Biology (6,696)
Biology 1002B (1,340)
Tom Haffie (863)
Lecture 16

Lecture 16.docx

3 Pages
Unlock Document

Western University
Biology 1002B
Tom Haffie

Lecture 16: Evolution of Multi-cellularity  What to see on the DNA picture o DNA binding sites o DNA methylation  Clicker question: o Which of the following regulation mechanism is not “epigenetic”  Epigenetics:  Cannot change the DNA sequence, not mutations o Not mutations  Persistent beyond the original conditions where the regulation is started o Last for the whole life  Lac binding is not epigenetics because lac varies,  Binding of Xist RNA is epigenetics, persistent, whole life will be inactive  Regulation of gene expression affords the possibility for specialization… o Genetic vs. epigenetics  Clicker question o “Multicellular life is monophyletic”  False  Multicellularity evolved several times o Some groups have some unicellular organism and some multicellular organisms o Multicelluarity has evolved multiple times  Volvocine algae provide a productive model system… o Chlamy unicellular o Organisms begin to live together o Then organisms are living together in a “cell wall” o Volvocine, lots of somatic cells, still have flagellum o Volvocine and chlamy common ancestor is 50MYA  Volvox o Some cells are big and some are small o ECM, extra cellular matrix  Volvox genus is not monophyletic o It has evolved 4 or 5 times  Volvox embryology o 1 cell divides in 2, 4, 8, 16 undifferentiated o A symmetric division is very important o The large cells will become reproductive cells o The small cells will become somatic cells o In a development stage, the cell is inside out, the flagellum is inside and reproductive cells outside o But then it flip itself, and the flagellum is outside and reproductive cells are inside, and respond to light o Reproductive cells will reproduce, and the somatic cells of parent cell will die  What kind of study would help to identify the genes that are important for multicellularity? o Maybe Use restriction endonuclease enzymes  Selectively cut out genes, or mutate them o Mutate volvox and see how it effects the cell, where is broken and etc. o Using southern blots, compare genome of chlamy and volvox o How do they make somatic cell and the reproductive cells, different kind of tissues  Clicker question o In what way would you predict that the volvox genome is different from Chlamydomonas  Genome size are not dramatically different  PCG have about the
More Less

Related notes for Biology 1002B

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.