Writing Project for 11/17/09

Writing project for next tuesday:

There appears to be  switch activated in underweight babies that leads to diabetes later in life. Early on, these individuals might be insulin resistant – so less glucose gets metabolized by muscle tissue. As a result, less energy is devoted to growth and building muscles and bones. On the flip side, more glucose is available for other tissues – like the brain and also infection fighting cells.  How might insulin resistance might be helpful for underweight neonates?

Insulin Resistance and Diabetes

On tuesday we are going to discuss some very interesting findings on diabetes and insulin resistance. Could there be any adaptive value to the trait of insulin resistance? For tuesday please read the following:

kuzawa-chapter-for-evolutionary-anthropology

Diabetes and Development

Grandmother hypothesis

New data on the grandmother hypothesis:

http://sciencenow.sciencemag.org/cgi/content/full/2009/1028/1

And, because it relates to a topic Dr. Appenzeller brought up – a bit about the evolution of long distance running:

http://www.nytimes.com/2009/10/27/health/27well.html?em

Evolution of Aging

Next week we will discuss hypotheses of aging.

aging

understanding-aging

age-old-question

Why do you think we age?

We will discuss several hypotheses of aging including:

Declining power of selection

Antagonistic Pleiotropy

Read about both with the attached readings.The writing project is:

Which is more powerful: natural selection for immunity that protects children from pneumonia or natural selection on Alzheimer’s disease? Explain why?

 

Thursday Discussion

Dr. Appenzeller’s article is here:

http://stroke.ahajournals.org/cgi/content/full/37/7/1754

On thursday we will finish our discussion of altitude topics. I am posting my lecture on altitude here:

High Altitude Populations

Go ahead and read read the slides above. I am not planning on giving the whole lecture, but I will show a few highlights.

I will assign readings and a writing project for next week soon! Check back tomorrow or wait until class…

Joe Alcock MD

High Altitude Adaptation

Tuesday 10/27/09

4:00 pm – 5:15 pm

Castetter Hall, Room 258

Title: Climate and Evolution of Human Adaptation to Hypoxia

 Otto Appenzeller MD

New Mexico Health Enhancement and Marathon Clinics Research Foundation

Dr. Appenzeller has done research on the physiology of  altitude adaptation among the Ethiopian highlanders. This population is one of the most interesting of high altitude human groups. They have unique alterations of their physiology that allow them to live at very high altitude – 10,000 – 11,000 feet of elevation – without any apparent hypoxia or ill effects.

This is a unique opportunity to hear about the research on this high altitude population as it relates to human evolution!

Joe Alcock MD

Sponsored by:

Visitors may find this map useful – Castetter is #21:

Writing Project for next week: re-posted

Writing project  assigned on 10/20/09 and due 10/27/09:
Some suggest that menopause evolved because grandmothers are more successful at passing on their genes by investing in grandchildren than in more babies of their own. Others argue that menopause is a consequence of modern medicine prolonging the lifespan of women past 60 when most pre-historic women would be dead. So in the past reproductive aging would have been in sync with aging of the rest of the body. In this view menopause reflects the early mortality in pre-history and is a gene-environment mismatch. There is evidence for and against both the “grandmother hypothesis” and the “artificial lifespan prolongation” hypothesis. Argue for or against either in your paper.
Extra credit:  Hormone replacement therapy. Is menopause a treatable deficiency disease? Write about the pros and cons of hormone replacement therapy from an evolutionary point of view. under which hypothesis, “grandmother” or “artificial lifespan prolongation” would you predict that HRT would be more helpful in promoting heath and preventing disease.  What does the data say? (This will take some research.)

Final Presentations – Preview

Tomorrow we will discuss the requirements for final projects.

Good presentations will include the following elements:

1) A description of a disease or a condition that affects human health.

2) Review or proposal of a disease hypothesis that incorporates an evolutionary point of view (adaptationist, historical) and/or alternative hypotheses (e.g epiphenomenon, null hypothesis, non-adaptationist). This might take the form of a “why” question of ultimate causation.

3) Or, a comparison of disease therapies from an evolutionary point of view.

4) Ideally, predictions of hypotheses can be presented, or data if evidence exists.

5) Speculations about the implications of a hypothesis. If you present a idea that you do not agree with, give the reasons why or why an alternative is preferred.

The remainder will be limited to 15 minutes with a minute or two for questions. Please practice your presentation to make sure it will fit into that time restriction.

Please email me at my gmail account if you have any questions about the presentations, or want me to preview an outline of your talk. I would be more than happy to answer questions by email or in person by appointment.

See you manana,

Joe Alcock MD

Reproduction, Morning Sickness, Menopause

Reproduction: Morning Sickness & Menopause
Morning Sickness – why does it occur; does it have a benefit to the fetus or mother?
Menopause – why do women cease to reproduce in middle age?
Readings:
1. Testing Menopause
2. Nausea and vomiting of pregnancy in an evolutionary perspective. Sherman PW, Flaxman SM. 2002. Am J Obstet Gynecol 186:S190-7.
3. evolutionary_obstetrics

4.Hill and Hurtado – Grandmother hypothesis

Preview: Writing project to be assigned on 10/20/09 and due 10/27/09:
Some suggest that menopause evolved because grandmothers are more successful at passing on their genes by investing in grandchildren than in more babies of their own. Others argue that menopause is a consequence of modern medicine prolonging the lifespan of women past 60 when most pre-historic women would be dead. So in the past reproductive aging would have been in sync with aging of the rest of the body. In this view menopause reflects the early mortality in pre-history and is a gene-environment mismatch. There is evidence for and against both the “grandmother hypothesis” and the “artificial lifespan prolongation” hypothesis. Argue for or against either in your paper.
Extra credit:  Hormone replacement therapy. Is menopause a treatable deficiency disease? Write about the pros and cons of hormone replacement therapy from an evolutionary point of view. under which hypothesis, “grandmother” or “artificial lifespan prolongation” would you predict that HRT would be more helpful in promoting heath and preventing disease.  What does the data say? (This will take some research.)

Writing Project

Writing project (due next tuesday).
Some have suggested that the age of weaning of infants from the breast is subject to  parent offspring conflict. For example, infants might want to breastfeed longer than the mother would like. Breastfeeding tends to suppress ovulation and delay pregnancy.   Give an evolutionary hypothesis for why infants might exhibit behavior that promotes longer breastfeeding.  What behaviors might these be? The infant has 1/2 maternal derived genes and 1/2 paternal derived genes; which of these would these be expected to prolong breastfeeding?

This is the article on aspirin and inluenza that I mentioned during today’s lecture:

http://www.nytimes.com/2009/10/13/health/13aspirin.html?em

The following s a wrap up of tuesday’s lecture:

Genetic conflict occurs between parents and between mothers and offspring. It is on of the most counter-intuitive ideas in evolutionary medicine.

Bottom line: babies do not always get along with their mothers, even while in the womb! Placentas do not get along with pregnant mothers either, with surprising results! This conflict arises from the fact that placentas are derived entirely from paternal genes. And of course the baby’s genes are 1/2 maternal and 1/2 paternal on average. Paternal-derived genes might benefit if more resources are delivered to the baby than the mother would like to give up. This sets the stage for a tug-of-war between genes from the mother and genes from the father.

Gestational diabetes provides a quick example: Glucose is a fuel that allows growth of the fetus. Paternal derived genes might cause increased glucose delivery to the fetus. Increased glucose causes the baby to grow slightly larger, but at some cost to the mother. The overall size of a baby might reflect a balance between paternal genes that increase the size of the fetus versus maternal genes that resist these increases. When the balance is tipped too far in favor of paternal genes, the mother may suffer from gestational diabetes.

This brings up all sorts of questions. For example:

1. Isn’t it bad for the baby too to be large, causing difficulties at birth? If the baby dies at birth it would be of no benefit to paternal derived genes to have a larger baby.

2. Shouldn’t the interests of baby and mother be in perfect alignment, since they are dependent on each other for successful reproduction?

3. Do paternally-derived “conflict” genes get expressed differently for one-night stands versus a long term committed relationship?

The answers are: yes, no, and yes.