Transcript Sex, Gender and What`s the Difference, Anyway?

Thoughts on Sex, Gender
and Evolution.
Marianne J. Legato, M.D.*
*With A Lot of Help from
Charles Darwin et al.
So we’ve
“Cracked the Genetic
Code”
and
“Defined The Human
Genome”
So?
What’s a chromosome?
What’s a gene?
How does it work?
What’s a “mutation?”
Who exactly was
Charles Darwin?
What did he say?
(And why should we care?)
1809-1882
What makes us
male or female?
XX
XY
Do we need two sexes?
(The Y chromosome only arrived
on the scene
about 300,000,000 years ago.)
Does Sex Impact Gene
Expression?
“Thousands of genes show sexual dimorphism
in liver, adipose, muscle and the brain: they
exhibit highly tissue-specific patterns of
expression.. “*
“We saw striking and measurable differences
in more than half of the genes’ expression pattern
between males and females. We didn’t expect that.
no one has previously demonstrated this genetic
gender gap at such high levels.”**
*Yang et al. Genome. 2006
**Thomas Drake, C0 investigator
Does every cell in our body have a sex?
Or are some parts of us androgynous?
Does every gene work the same way
in men and women?
So do we have (and why do we need)
sex-specific tissues and organs? (I think we
do, and if you believe Darwin, it equips us
perfectly for the environment. )
What are genomic
scientists
doing
worrying about
saying
What Scientists are Doing
• Taking genes out and
inserting others
• Making biologic
specimens capable of
reproduction
• Giving us a precise
picture of who we are
and the possibility of
changing it.
Evolution is no longer
“natural selection”.
With the advent of
genetic engineering,
we can- and are- changing
very nature
of created life.
Imagine:
Human cloning
Engineering the characteristics of new
(human?) beings prepared for specific
functions (like war, for example)
Prolonging the life span indefinitely
Creating new biological systems capable
of reproduction (and if this is so, also
probably capable themselves of evolution)
Genomic Science and Sex
• Will it be an advantage to
retain two
sexes?
• If we eliminate biological
sex in new forms of life
before we understand the
nature and extent of its
expression on genes, what
will be the consequences to
form and function?
• Does the study of the
impact of sex on gene
expression deserve more
attention?
What are scientists
worrying about?
Consider the Impact Of
Genomic Science On
• The environment
• Economics
• The nature and number of living beings
• The redistribution of power (planned and
unplanned)
"Ever since the discovery of
nuclear fission, the possibility
of powerful explosives based on
it had been very much in my
mind, as it had in that of many
other physicists. We had some
understanding of what this
might do for us in the war, and
how much it might change the
course of history.”
“I chide Goldblatt* for the
incredible naiveté he and the
Defense Sciences Office displayed
in not thinking its plans to enhance
humans would arouse controversy….
didn’t it occur to anybody that you
were playing with fire?”
Joel Garreau
(in Radical Evolution)
*Michael Goldblatt, former head of the Defense Science Office
What Scientists are Saying
• We are changing the rate and
mechanisms of the evolution of living
things profoundly.
• If there is a choice between
preserving the earth in a viable state
or continuing the human race, we will
probably opt to continue the race.
“My guess is that if the question of human extinction is
ever posed clearly, people will say that it’s all very well to
say we’ve been a part of nature up to now, but that at this
turning point in the human race’s history, it is surely essential that
we do something about it; that we fix the genome to get of rid
of the disease that’s causing the instability, if necessary, we clone
people known to be free from the risk, because that’s the only way
in which we can keep the human race alive.
A still, small voice may at that stage ask, but right does the
human race have to claim precedence for itself. To which my
guess is the full-throated answer would be, sorry, the human
race has taken a decision, and that decision is to survive. And,
if you like, the hell with the rest of the ecosystem.”
Sir John Maddox,
Former editor of Nature
Prometheus,
who gave men fire.