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Printable Handouts
Navigable Slide Index
- Introduction
- Scheme of meiosis
- The central dogma of meiosis
- Nondisjunction frequencies in Drosophila
- A revised view of meiosis (1)
- Study of chromosome segregation by aberrations
- Understanding meiosis with a mutational approach
- A revised view of meiosis (2)
- Problems with the mutant collection
- Three tools changed the study of meiosis
- The 1996 P element screen
- Genes defined by large-scale screen for mutants
- The 2004 "FLP-FRT" screen
- Screen for meiotic mutants
- Scheme of the germline clone screen
- Summary of mutants obtained from the screen
- Critical screens and studies by others
- Screens lead to insights into biological processes
- Pathway of meiosis
- Mutational analysis of Drosophila female meiosis
- Spindle formation in Drosophila
- Achiasmate segregation in female Drosophila
- Model of meiosis in Drosophila
- Meiotic spindle at the metaphase arrest
- Heterochromatic pairings and segregation (1)
- Heterochromatic pairings and segregation (2)
- A screen for dosage sensitive genes
- Df(3L)66C
- Mapping the gene with the dosage affect
- What do we know about the mtrm gene
- What is the function of the mtrm gene
- Nondisjunction affected by the Mtrm-Polo balance
- Mtrm physically interacts with Polo kinase (1)
- Mtrm physically interacts with Polo kinase (2)
- Mtrm physically interacts with Polo kinase (3)
- Expression patterns of Mtrm and Polo
- Diagram of oogenesis in Drosophila
- The timing of expression of Mtrm and Polo (1)
- The timing of expression of Mtrm and Polo (2)
- In metazoans Polo activity triggers NEB
- mtrm mutation cause precocious NEB (1)
- mtrm mutation cause precocious NEB (2)
- Mutation in polo suppress Mtrm affect on NEB
- Two proteins control NEB and restart of meiosis
- A model for the control of NEB
- What is between NEB and nondisjunction?
- Karyosome in mtrm heterozygotes
- Spindle formation and NEB in wt female (1)
- Spindle formation and NEB in wt female (2)
- Spindle formation in mtrm heterozygote (1)
- Spindle formation in mtrm heterozygote (2)
- The chromosomes in mtrm heterozygote
- Metaphase spindle in mtrm heterozygote (1)
- Metaphase spindle in mtrm heterozygote (2)
- Chromosomes re-aggregate at a metaphase plate
- Acknowledgements
Topics Covered
- Identification of genetic material
- The central dogma of meiosis
- Nondisjunction frequencies for the Drosophila genome
- A revised view of meiosis
- Chromosome segregation
- A mutational approach to understanding the meiotic process
- Development of tools to study meiosis in Drosophila females
- The 1996 P element screen
- Genes defined by our first large-scale screen for new meiotic mutants
- The 2004 'FLP-FRT' screen
- Germline clone screen
- Achiasmate (nonexchange) segregations are preceded by heterochromatic pairings
- Mtrm and Polo
Talk Citation
Hawley, R.S. (2018, May 31). The genetic analysis of meiosis in Drosophila melanogaster females [Video file]. In The Biomedical & Life Sciences Collection, Henry Stewart Talks. Retrieved November 7, 2024, from https://doi.org/10.69645/OOAT7874.Export Citation (RIS)
Publication History
Financial Disclosures
- Prof. R. Scott Hawley has not informed HSTalks of any commercial/financial relationship that it is appropriate to disclose.
The genetic analysis of meiosis in Drosophila melanogaster females
A selection of talks on Genetics & Epigenetics
Transcript
Please wait while the transcript is being prepared...
0:00
Good afternoon.
My name is Scott Hawley,
from the Stowers Institute of
Medical Research in Kansas City, Missouri.
And I'm here to do a couple of things.
I have an easy job, which is to talk
to you about the genetic analysis of
meiosis in Drosophila
melanogaster females.
And I have a hard job,
which is to make you care.
And the reason it's
difficult to make you care,
is that whenever I mentioned the word
meiosis, I watch people's eyes glaze over.
They've had meiosis in Montessori school
that had five, six, seven, eight,
nine times.
And frankly, they're really tired of it.
And the reason they're tired of it
has to do with this next slide.
0:34
If you look at this next slide,
which I took out of a textbook,
the main problem with this slide is if you
didn't understand meiosis before you saw
this slide it's kind of
hopeless thereafter.
As you see upon the top,
there's all this chromosomal fettuccini.
We even added a mushroom,
which is actually the nucleolus.
And just to make sure you could digest it
all, we even added a replication fork.
I'm not sure there's all those Greek
names leptotene, zygotene, pachytene,
diplotene, diakinesis,
they're all Greek for prophase.
And if you look down in
the middle of the bottom row,
I don't know what that
middle chromosome is doing.
But it's not metaphase II.
In other words, it's really impossible
to try and understand what's
going on in meiosis, by looking at
a complicated, overdrawn slide like this.
And that's why I wanna try and simplify
meiosis for you before we even begin.
1:23
This slide shows the meiosis the way the
people in my laboratory think about it.
It's an idea that we've taken
from the late Barbara McClintock,
who simplified meiosis back in the 1930s,
by pointing out that if you get rid of all
that Greek, if you get rid of
all those complicated diagrams.
You can think about meiosis as a process
where three things have to happen.
Chromosomes have to pair, they have
to match up along their length, so
that the copy of chromosome one that was
obtained from the organism's father,
lines up against the copy of chromosome
one that was obtained from the organism's
mother, and so on.
So they have to pair.
They have to match by homology
along their entire length.
Once they pair, they have to
undergo exchange or crossing over.
If you went to private school or
recombination or chiasma formation,
I don't care what term you use,
as long as you realize that exchange or
chiasma formation serves the vital
function of interlocking paired homologs.
That's what meiosis does it makes
sure that what was paired remains
stuck together as these chromosomes go
throughout the ballet, which is meiosis.
And then finally,
at the first meiotic division,
chromosomes have to
segregate from each other.
They have to disjoin if you will.
So that each homologue goes to opposite
poles, and we end up with two daughter
cells, each of which contains
a haploid complement of chromosomes.
If we're talking about humans,
that means we have to go from a cell
with 46 chromosomes, to two daughter
cells each of which have 23.
If you're talking about my organism,
which is Drosophila melanogaster females,
they start with eight chromosomes at
the beginning of meiosis and the two
products of the first meiotic division,
each of which each has four chromosomes,
usually one of each homologue if
everything has gone correctly.
The second meiotic division we're not
going to worry about very much it really
is a haploid mitosis.
Unfortunately, as you're going
to see in the next slide,
this is rather a simplified
description of meiosis,
because we can't count on
exchange always occurring.
In this slide, we look at
the frequency of recombination for