Course Announcements
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Please complete the pre-course survey (thanks to all who already have)
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EC if completed by tonight
Will remain open until Thurs of week 2 (for #finaid/CAA purposes)
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Podcast?
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Readings update:
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I added Main Points to the website
I deleted the course on Perusall 🤣
But, I like the idea y’all’s idea of being able to earn EC for really engaging, so I’ll be giving EC
on responses on the Form that I really like (thoughtful, insightful, inquisitive, etc.)
RR (Google Form; Thanks, Homero!)
If you answer before class, chance for full credit
- Form will remain open; chance for ½ credit for week following class
COGS 169
Lecture 01:
The History of
(Behavior) Genetics
…and how to read scientific papers
Introduce yourself to the people next to/near you
1.
2.
3.
4.
Name
Major / what you like to learn about
Something cool you learned about science once
A piece of interesting news you recently heard / learned about
Ancient Times
1
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~5000 years ago (Egypt + Near East): Deliberate breeding of animals for
particular traits; “several distinctive varieties of cattle and dogs are portrayed
in ancient Egyptian art”1
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Ancient Greeks had a concept that behavioral traits were passed down
through families: “Ye are of the line of men that are sceptred kings ... for no
churls could beget sons like you” (Book IV of Homer’s Odyssey, trans. 1909,
p. 49); similar concepts in Hebrew scriptures
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Plato writes in The Republic of the “desirability of matching the best with the
best, and rearing their offspring with special attention”1 (also knows it’s not a
guarantee and argues for education and the ability to demote the elite)
https://socialequity.duke.edu/wp-content/uploads/2022/02/The-Golden-Age-of-Behavior-Genetics_.pdf
Image: By Didia - Foto: Own work, Painting: Ancient Egyptian Painter, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=12101672
Nature vs. Nurture Debate (17th-19th century)
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term believed to originally come from The Tempest (play; William
Shakespeare; 1610)
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Modern arguments traced to 17th c. philosopher John Locke and 19th c.
naturalist Charles Darwin
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Locke (nurture) - argued that our minds are blank sheets of paper molded by Education;
rejected the idea of inborn ideas but accepted innate characteristics
Darwin (nature) - placed human behavior in framework of nature via biological evolution;
human behavior shared ancestry with other animal species and subject to evolution and
variation via natural selection
Image: Scene from Shakespeare's The Tempest by Hogarth; circa 1735
Francis Galton (late 1800s)
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Argues nature plays a way bigger part than nurture: when
it comes to differences among humans, environment
matters….but not nearly as much as heredity
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Studied “hereditary genius” and “the comparative worth
of different races”
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Noted that “genius” clustered within families; with the number of
eminent relatives decreasing as familial ties weakened
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Proposed the study of twins to get a sense of the relative
effects of nature and nurture (although he thought all
twins were genetically identical)
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Developed the correlation coefficient
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Coined the term “eugenics” and absolutely was a
Eugenicist himself
Image Source: Britannica
Eugenics (1920s)
A generous definition: “The encouragement of the more useful members of
society to have more children and the less useful to have fewer.”1
From our textbook: “a movement that saw the future salvation of humanity in
scientifically planned selective breeding”
A clearer definition: “The scientifically erroneous and immoral theory of “racial
improvement” and “planned breeding”
Adopted by the Nazis to justify their inexcusable treatment of Jews and people
with disabilities (among many other minority groups).
Y’all, the Nazis held meetings to figure out how to legalize their policies…using
the US’s racists policies as their model and guide.
1
https://socialequity.duke.edu/wp-content/uploads/2022/02/The-Golden-Age-of-Behavior-Genetics_.pdf
History of Behavioral Genetics: A Play in Four Acts
1.
2.
3.
4.
Biometricians
Mendelians
Polygenicity
Molecular Genetics
Act 1: Biometricians (1869-1900)
Understood genetics to be best studied by examining correlations of traits, in
different kinds of relatives
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Classic twin study: comparing MZ and DZ twins
Image Source: https://www.sri.com/press/story/want-to-know-if-its-nature-or-nurture-look-at-twins/
Act 2: Mendelians
1866 Gregor Mendel and his pea plants
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Inheritance arose from action of
distinct units (genes)
Rediscovered in 1900
We’ll discuss this in more detail in a coming lecture.
Mendelians vs. Biometricians
Blended Inheritance (Biometricians using
correlations)?
Discrete Units that produced clearly distinct
phenotypes (short vs tall pea plants)
A common theme in genetics/science: popular opinion and scientific
inquiry swings far one way, then far the other, and then truth is
somewhere in the middle.
The early hunt for Mendelian transmission in behavioral
phenotypes
1. Ernst Rudin - studied siblings of individuals with schizophrenia; hypothesis of
simple Mendelian transmission; results did not fit such a model; proposed a
two-gene recessive model (roughly fit his data)
2. Charles Davenport - believed he had discovered simple Mendelian inheritance
patterns for “the wandering impulse” and “feeble mindedness”
Was Mendel wrong?
Was Mendel wrong about inheritance?
Nope.
Many human conditions follow simple mendelian inheritance
patterns (and were discovered at this time): Albinism, various
metabolic conditions (Gaucher disease, PKU), neurological
disorders (Huntington’s Disease)
Thomas Hunt Morgan identified Mendelian genetic variants in
the fruit fly and established the role of chromosomes in
heredity
…so Mendelians were gaining ground.
…but what about height?
Image Source: https://www.expii.com/t/mendelian-genetics-principles-of-inheritance-laws-10970
The 20th Century: Psychology
Psychology (the primary people studying behavior) were very much in the camp
of nurture at the time:
Give me a dozen healthy infants, well-formed, and my own specified world to
bring them up in and I’ll guarantee to take any one at random and train him to
become any type of specialist I might select – doctor, lawyer, artist,
merchant-chief, and yes, even beggar-man and thief, regardless of his
talents, penchants, tendencies, abilities, vocations, and race of his ancestors.
- John B. Watson (1925)
1950s: The rise of social science combated the nurture nature (error in notes
originally) arguments from the eugenicists.
The Modern Era: The Field of Behavior Genetics (~1960)
1960: Textbook Foundations of
Behavior Genetics by Fuller and
Thompson1
1970: The Journal Behavior Genetics is
started
1972: Behavior Genetics Association
forms- 69 members grew to 270 in
2004
1
https://gwern.net/doc/genetics/heritable/1960-fuller-behaviorgenetics.pdf
Ronald Fisher
Karl Pearson
Infinitesimal model:
Liability-threshold model:
Argued that a trait could be influenced
by a very large number of Mendelian
genes, each with a very small effect
Psychiatric disorders are not
quantitative traits
unified Mendelian and biometric
worldviews
Fisher Image: https://magazine.amstat.org/blog/2018/10/30/sih-fisher/
Pearson Image: https://magazine.amstat.org/blog/2018/10/30/sih-kpearson/
Heritability refers to the underlying
liability for a trait (not the dichotomous
trait itself)
Act 3: Polygenicity (1960s-1980s)
1967 Gottesman and Shields
publish “A polygenic theory of
schizophrenia”
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proposed that “the genetic
risk for schizophrenia can
be best described by a
combination of Fisher’s
infinitesimal model of many
genes of very small effect
and Pearson’s
liability-threshold model”
Image: https://www.expii.com/t/polygenic-definition-examples-10184
Act 4: Enter Molecular Genetics (1980s-present)
1983: use of molecular markers to map a human genetic disease via linkage
analysis (Huntington’s chorea; Gusella et al.)
Competing models at the time:
1.
2.
Genetic epidemiology (from the biometricians) - applied liability-threshold
models to family/twin/adoption studies; did not use molecular markers;
assumed polygenicity
Linkage Studies (in line with Mendelians) - assumed the genetic influences
on behavioral traits resulted from “Mendelian” loci; used linkage to detect
these
Image Source: https://biology.mit.edu/faculty-and-research/areas-of-research/genetics/
Genome Projects
1995: First whole organism genome
sequenced (Haemophilus influenzae)
1996-2001: Lots more organisms:
yeast (1996); C. elegans (1998); fruit fly
(2000)
2001: Human Genome Project (HGP) first “complete” draft of the human
genome (public and private versions)
2022: First gapless human genome
released
President Bill Clinton is joined by Craig Venter (left), president of the
Celera Genomics Corporation, and Francis Collins, chairman of the
Human Genome Project, at the National Institutes of Health, at White
House meeting to announce that the two groups' scientists have nearly
completed mapping the human genetic code. (Photo by Harry
Hamburg/NY Daily News Archive via Getty Images)
Technological advances in Act 4
PCR
Recombinant DNA technologies
SNP Genotyping
Next Generation Sequencing (NGS)
Gene Editing (CRISPR-Cas9)
…we’ll discuss these (and others) in a coming lecture and throughout the course
Controversies in Behavior Genetics
Group Differences: Work studying the genetic differences in psychological traits
based on race, sex, or social class
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(unsupported) claims that genetics could explain the black-white gap in IQ
scores
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Proposed studies of the differences in frequency of criminal behavior based
on race (blacks and whites in the USA)
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Comments made (by economist Lawrence Summers) on the reason there is a
shortage of women at the highest level in the scientific professions could be
due to biological differences between the sexes with males having greater
variance
Student Questions: RR01
Can you explain “pleiotropy”. It was introduced on the first page and weaved in through the reading
but, even after looking it up I am still a bit confused. Is it a single gene that causes multiple
phenotypic effects? -Wyatt
YES. That’s exactly it!
One mutation…multiple downstream effects.
An example? There are LOTS in the fruit fly! Scientists often identify a visible phenotype and then find that the
underlying mutation has “pleiotropic” (many) effects
vestigial, for example…where fruit flies have “miniwings” and are unable to fly). The same mutation also affects
the number of egg strings in a fly’s ovary and decreases lifespan.
So let’s talk about the statement from the reading: “waltzing [ataxia; abnormal gait] was recessive, but concluded
that…its inheritance did not support a Mendelian model. This is an early case of being misled by pleiotropic
effects of a mutation: he failed to consider the possibility of reduced viability of the homozygotes, a common
feature of neurological mutants”
Student Questions: RR01
I think I am most confused about Karl Pearson's liability threshold, I felt more confused about the
tallness analogy. Applying this to schizophrenia does this mean that someone could have it or they
don't, or that they don't meet the threshold/requirements but could develop it later? -Anais
A qualitative/discrete trait for tallness would be “tall” and “not tall”
Not how we often think about height, but you could classify it that way.
But, when we think of a condition like Schizophrenia, we often do think of it as “has” or “does not have”
However, the liability threshold suggests that there are many factors that contribute to one having Schizophrenia. People
could have a few factors and not reach the threshold for “has Schizophrenia” (in fact, this seems to be the case…we’ll talk
about this!)
So the liability threshold suggests that there are accumulating factors (genetic, environment, etc.) that once they reach
above a threshold, the individual presents with what clinicians would diagnose as Schizophrenia.
Student Questions: RR01
Is evolutionary synthesis to behavioral studies same as neurogenetics or is it precursor to
neurogenetics? -Jungwoo
I’d say it’s separate from but related to neurogenetics.
The quote from the reading: “Hirsch’s [quantitative genetic analysis brought to study of
behavior] effort to win recognition for the role of genes was based on his recognition that
behavior had to be understood in the context of evolution…By introducing the element of
population genetics, Hirsch brough the modern evolutionary synthesis to behavioral studies”
In other words:
- Population genetics involves studying whole groups, rather than individuals
- Also, evolution is a thing
- Many behaviors are evolutionarily conserved
- If they’re conserved across evolutionary history, there is a genetic component
Student Questions: RR01
Studying fruitflies was very popular back in the day, however, logistically how was
this possible? Fruitflies are so small, I cannot imagine them being easy to "catch"
and genotype/study. As an ex-lab assistant who worked in a mice lab, I understand
that it is pretty difficult organizing mice and breeding/genotyping them. Since mice
are much larger than flies, what was the process like? - Juliana
1850s: microscope becomes
usable and reliable for looking at
cells and viruses
1600s: microscope invented
Leeuwenhoek with his microscope. Oil painting by
Ernest Board.
(https://wellcomecollection.org/works/v7rv44en)
Thomas Hunt Morgan’s Columbia Fly Room.
1960s: Benzer “found that when flies are
banged to the bottom of a test tube, they run
like crazy to the light, a phenomenon known
as fast phototaxis” [source]
“If you're doing genetics, it's important to work
with an organism where you can work on
populations, because if you run a rat through a
maze over and over again, it takes weeks to get
any significant amount of data that would be
statistically significant. But if you have a bunch
of flies, they all have the same genotype, and
when you run them through a maze, you
immediately get to do hundreds of flies at
once” -Benzer
Student Questions: RR01
The various experiments mentioned at the beginning of the article are all exploring
the relationship between behavioral traits and genes. However, the article concludes
that contemporary research leans more towards the study of environmental
influences and gene-environment interactions, especially in humans, which has
become much more sophisticated than it was 100 years ago. Why is this shift? -Gege
A few reasons.
Primarily: it’s possible to study now.
Secondarily: we’ve tried studying just genetics and just environment and we keep
finding stories where the environment and interactions between GXE matter
Big Questions
1.
What’s the point of understanding the genetic basis of…
a.
b.
c.
General traits (speech, language, sleep, mating, etc.)
Disorders (Anxiety, Schizophrenia, Insomnia, etc.)
Human differences (i.e. sexual orientation, penchant for aggression)
2.
What do/can/should we do if we find a gene for disease X?
3.
If this is a class on genetics of behavior…what do we think about a role for
the environment? Where are we on the nature vs. nurture debate today?
How To Read a Scientific Paper
From your classmates:
Hi! I honestly just have a hard time reading text like this, especially text like from the textbook. I think I am just not accustomed
to scientific text like this, but it sometimes is difficult for me to interpret the information and put it into a summary. I hope it
gets easier throughout the quarter.
My hope/expectation is that in a week or two, the textbook is easier than it is now. And that in 5-6 weeks, reading
scientific articles gets easier. But, it will take much longer before it is “easy”...but it only gets to “easy” if you keep doing it!
Also, we’re here to help!
This article took me a couple of hours to read through and understand to my best effort. I am hoping to go over the fruit fly
experiment(s) during class.
The fly experiments will be discussed in a lot of detail in coming lectures. My goal here was for you to get a ssense that
such experiments happened/existed/taught us stuff…with understanding of the details in coming weeks.
"The origins of behavioral genetics" was a bit of a tough read. I will be double checking the definitions of certain words such
as "phototaxis" & "geotaxis"
We’ll be discussing these soon! (phototaxis = moving toward like; geotaxis = moving in response to gravity)
Article Type
Summary
Primary literature
scientific papers peer-reviewed and published in Academics (…typically people who
academic journals describing research done by
study something similar to the
the authors
authors of the paper)
Review Articles
a peer-reviewed paper summarizing the work
done by scientists in a particular field or on a
particular topic
Scientific Magazines
(i.e. Scientific
American; the Atlantic)
Book chapters /
textbooks
Who It’s Primarily Written For
Academics
Pieces written on scientific topics
The general public
Similar to review articles (in that they summarize
work on a topic or set of topics) but often these
are not peer-reviewed
Academics or students
Hidden Curriculum: Publishing in an academic journal
The Process:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Do science
If you find something interesting, write a paper
Decide where you’re going to submit that paper and format paper for that journal
Editor decides if paper should go out for review
Other scientists carry out peer review (typically 2-3 people; no compensation)
Editor decides if paper will be published, needs revision, or will be rejected with reviews in hand
Typically: author revises paper with review feedback
Scientists re-review the paper
Editor decides if paper will be published, needs revision, or will be rejected with reviews in hand
Another round or reviews ensues, paper is rejected, or paper is accepted for publication
Scientist pays journal to publish paper; if open access, scientist pays more (hundreds to thousands)
Paper is published
Hidden Curriculum: Journal Prestige
Different journals have different levels of “prestige”:
Two journals are the “top” journals: Science & Nature
One journal, depending on field is right in line: Cell
If medical: Lancet and NEJM are tops
There’s something called an “Impact Factor” the higher the number, the more
“prestige” a journal has. All of the above have an IF >45…which is high.
Just “below” these: PNAS (but a really great journal)
There are hundreds of other journals!
Hidden Curriculum: How Science (often) Happens
Grad students and postdocs join a lab.
They do the work, in consultation with the person who runs the lab (PI).
When they graduate/move on, they (sometimes) take some of their work and
(always) take all of their experience and training with them.
So, scientists are often influenced by their training. Sometimes they do very
similar work. Sometimes they go a very different path.
But, who they worked with and what they worked on is always with them.
The same goes for what we research/write/publish. (Note: Drosophila bias in
history/review reading)
How primary research papers are (typically) organized
1. Title
2. Abstract
3. Introduction
4. Methods
5. Results
6. Discussion
7. Conclusion
8. References
9. Supplement/Appendix
Hubbard, K. E., & Dunbar, S. D. (2017). Perceptions of scientific research literature and strategies for reading papers
depend on academic career stage. PloS one, 12(12), e0189753.
A suggested approach…
1.
2.
Find a good place/environment to read
Read: Title + Abstract
---- Decide if you want to read further
3.
Skim the paper (~15min)
---- Decide if you want to read further
4.
5.
Read the introduction (the less you know, the more carefully you read)
FIGURES! (What’re the main points?)
---- It’s probably been an hour at this point
https://www.kmshannon.com/posts/2018-07-21-reading-research-papers/
A suggested approach…continued
6. First pass through the full paper
7. Second pass through the figures (nitty gritty!)
8. Second pass through the paper (critical eye)
---- At this point you should be able:
1.
2.
3.
To explain what was done in the paper
Describe what you’ve learned
Think critically about the results/points in the paper
https://www.kmshannon.com/posts/2018-07-21-reading-research-papers/
Activity: Beginning to read a scientific paper
1. Read: Title +
Abstract
2. Skim the paper
(~15 min)
3. Read the
introduction
4. FIGURES!
This will be the first full scientific research study required to read/used in class. Good idea to start early!
What could/would it look like to use ChatGPT for this?
[DEMO]