04/26/12

Name:

BIOL 116 Section:

Before the lecture starts, answer the following.

1. How would you define race?

2. How many races do you think there are?

3. What are they?

4. How do you decide which race someone belongs to?

5. Where do your ideas about race come from? What are the sources of your information?

6. Write the race below the picture of each of the following children:

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Genetic Diversity II

Why We are So Similar

The Meaning of Race from a Biological Perspective

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Genetic Diversity IIWhy We are So Similar

The Meaning of Race from a Biological Perspective

I. The Science of Classification II. Brief History of Human Racial ClassificationIII. Traditional Racial GroupingsIV. Human Genome ProjectV. The Power of an Illusion

I. The Science of Classification

A. Classification Hierarchy

TAXON HUMAN SHARED CHARACTERISTICS

Kingdom Animalia multicellular, movement, eat & digest other organisms

Phylum Chordata notochord (backbone)

Class Mammalia hair, mammary glands

Order Primates fingers, flat nails

Family Hominidae upright posture, flat face, large brain

Genus Homo double curved spine, long life span, long youth

Species Homo sapiens chin present, high forehead, thin skull and bones

Races, Types,Strains, Groups, Subspecies

? Skin color, geographic location, hair texture, facial features?

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Over long periods of time, with no interbreeding, populations begin to show differences from one another.

Unique ancestors for each group.

Ancestors of the different populations: Migrate away from the original area.

No exchange of genes between the ‘unique’ ancestors due to Reproductive BARRIERS to breeding. Therefore, since there are barriers to rbreeding, when groups of organisms form subspecies, we often find a definite geographical separation and/or ecological, temporal, and behavioral differences. *

B. How do populations of organisms accumulate differences?

*Ecological: Live in different parts of the same area (Ex: mountains/low-lands) Temporal: Are active at different times of the day Behavioral: Mating rituals are different; Language

C. There are ‘rules’ so that classification is performed scientifically.

1. The classifier must choose the trait(s) used to assign individual organisms into specific groups.

The traits chosen will define that group.(i.e., “You are a member of this particular group if you have *this* trait.”)

a) All of the members of a group must share the trait(s) chosen to define the group, and the chosen trait(s) cannot be found in individuals placed in a different group. There should be ‘pure’ groups.

b) If the traits chosen form a meaningful classification, it should be clear into which group all individuals should be found.

2. Groups that are tightly defined follow the above rules for classification. Tightly defined classification schemes are scientifically (biologically) valid.

D. There is some level of subjectivity when scientists classify any organism:

What characteristics do you use when separating groups?

When do you stop separating (Lumpers and Splitters)?

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RULESaccording to the biological science of classification (taxonomy)

II. Brief History of Human Racial Classification

A. Ancient peoples: Greeks had no word for ‘race’.

B. 1500-1600s: Trade routes became established

C. Carolus Linnaeus (1707-1778)

1. Americanus2. Europeaeus3. Asiaticus4. Afer

D. Johann Friedrich Blumenbach (1752-1840)

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“Caucasian variety. I have taken the name of this variety from Mount Caucasus, both because its neighborhood, and especially its southern slope...in that region, if anywhere, it seems we ought with the greatest probability to place the [original forms] of mankind”.

E. 2000 U.S. Census

The most profound change to the question on race for Census 2000 is that respondents are allowed to identify one or more races to indicate their racial identity.

The minimum categories for race are now:

American Indian or Alaska NativeAsianBlack or African AmericanNative Hawaiian or Other Pacific IslanderWhiteSome Other Race (Intended to capture responses such as Creole)

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Many of the primary categories also contained additional checkboxes or write-in areas to further define the category. For example, American Indian or Alaska Native - - contained instructions for respondents who check the box to print the name of their enrolled or principal tribe. There were six specified Asian and three detailed Pacific Islander categories shown on the Census 2000 questionnaires, as well as ‘Other Asian’ and ‘Other Pacific Islander’ which have write-in areas for respondents to provide other race responses.

III. Traditional Human Racial Groupings

A. The traits used for traditional racial groupings primarily are based on outward appearance.

1. Skin color: Background

Skin color is determined by the amount and type of the pigment melanin in the skin. Melanin comes in two types: phaeomelanin (red to yellow) and eumelanin (dark brown to black). People with light complexioned skin mostly produce pheomelanin, while those with dark colored skin mostly produce eumelanin.  In addition, individuals differ in the number and size of melanin particles.  The characteristic phenotype of fair skin, freckling, and carrot-red hair is associated with large amounts of pheomelanin and small amounts of eumelanin.

Studies suggest that both amount and type are determined by over 10 genes and several SNPs*, which operate under incomplete dominance. One copy of each of those genes is inherited from the father and one from the mother. Each gene may have several possible alleles. Therefore, a great variety of different skin colors will result.

Other factors involved include: 1) Some people have almost colorless skin and, therefore, red cells in blood flowing close to the skin affect the color, 2) Hormones may also affect skin color particularly during pregnancy and in birth control pills, 3) To a lesser extent, the color is affected by the presence of fat under the skin and carotene, a reddish-orange pigment in the skin. Skin color is a complicated trait and there are many other factors involved.

Advantages of Dark Skin.

Skin pigment protects against UV, so protects against the aging of the skin- wrinkling and ‘age’ spots. Melanin also helps prevent sunburn damage and, skin cancer.  In the United States, approximately 44,200 people get the most severe form of skin cancer, melanoma, every year, and about 7,300 of them will eventually die from it.  Those at highest risk are European Americans.  In Australia, the lifetime cumulative incidence of skin cancer approaches 50%

Tanning is primarily an increase in the number and size of melanin granules due to stimulation by ultraviolet exposure. Some light skinned northwest Europeans have lost all or most of their ability to tan (produce eumelanin). Their skin burns and peels rather than tans. They have a 10 times higher risk of melanoma than African Americans.

*This does not include several types of albinism.

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Another serious effect of UV radiation is the break-down of folate, an essential vitamin B needed for cell division and producing new DNA. Pregnant women in particular require large amounts of folate to support rapid cell division in the embryo. Women of reproductive age are advised to take folate supplements to prevent serious birth defects such as spina bifida (neural tube defect).

Although not complete, the advantages of dark skin also may include an added barrier to bacterial and other microbial infections.

Advantages of lighter skin

In regions away from the equator, where UV levels are lower, humans are fairer so as to allow enough UV radiation to penetrate their skin and produce vitamin D. Vitamin D is essential for maintaining healthy calcium and phosphorous absorption, thus promoting bone growth. Calcium is also necessary in adults to maintain normal heart action, blood clotting, and a stable nervous system. In addition, a deficiency in vitamin D may result in rickets disease in children and osteoporosis in adults. Females have lighter skin than males (In general, they produce 3-4% less melanin than males). This may be due to the higher calcium needs of women during pregnancy. In addition, women who had prolonged vitamin D3 deficiencies as girls have a higher incidence of pelvic deformities that prevent normal delivery of babies.

Evolutionary studies suggest that:

1. From ~1.2 million years ago to less than 100,000 years ago, after the loss of most of our body hair, the ancestors of all people alive were from Africa and had dark skin.

2. As populations began to migrate, the evolutionary constraint keeping skin dark decreased proportionally to the distance North a population migrated, resulting in a range of skin tones within northern populations.

3. At some point northern populations experienced positive selection for lighter skin due to the increased production of vitamin D from sunlight and the genes for darker skin disappeared from these populations.

4. This may have been increased due to agriculture which altered the diet of Northern peoples, requiring them to produce more of their own vitamin D.

That is the case with Eskimos and other inhabitants of northern Alaska and northern Canada. "Looking at Alaska, one would think that the native people should be pale as ghosts." One of the reasons they're not is that their traditional diet is rich in fish and other seafood. They've consumed huge doses of vitamin D, so they haven't had to undergo the same reduction in pigmentation that would otherwise be required at such high latitudes. "What's really interesting is that if these people don't eat their aboriginal diets of fish and marine mammals, they suffer tremendously high rates of vitamin D-deficiency diseases such as rickets in children and osteoporosis in adults." A similar problem occurs when darker skinned people move to Northern latitudes. Advances in nutrition have larger overcome this problem.

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http://magma.nationalgeographic.com/ngm/0211/feature2/online_extra.htmlhttp://en.wikipedia.org/wiki/Skin_colorhttp://anthro.palomar.edu/adapt/adapt_4.htm

Skin color basically becomes a balancing act between the demands of photo-protection and the need to create vitamin D in the skin. Therefore, ancient humans were under selective pressure for skin color in the range that would protect them against too much UV yet allow enough in to create vitamin D.

Populations with similar pigmentation may be genetically no more similar than other widely separated groups.

2. Does skin color follow the rules for biological classification?

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The in-between between the extremes:

There is a geographical pattern with skin color, BUT the pattern is generally found on a continuum. There are no definite boundaries or barriers between one skin shade to the next.

Where do we draw the lines to separate people? Who chooses?

B. Traditional racial classifications use more than one trait:

C. Unclassifiable groups

D. If traits used for the traditional racial classifications aren’t tightly defined, then which traits should be chosen to classify humans? Some possibilities follow:

1. Traits of medical importance, such as resistance to certain diseases?

2. Traits with nutritional importance, such as lactose intolerance?3. Other physical traits, such as fingerprint patterns?

1. Traits of medical importance, such as resistance to certain diseases

Example:

If we use malaria resistance as our defining characteristic, our races would look like this:

Race Includes people from: Malaria-resistant race: Tropical Africa

Southern IndiaArabian PeninsulaSoutheast AsiaNew GuineaMediterranean basin

Malaria-nonresistant race: Northern EuropeSouthernmost Africa

2. Traits of nutritional importance?12

Something to think about: Is everyone in these populations either Malaria-resistant or Malaria-nonresistant?

Example: Lactase production in adulthood.

Race Includes people from:

Lactase-positive race: Northern & Central EuropeArabiansNorthern IndiansWest Africa

Lactase-negative race: Southern EuropeEast AsiansAboriginal AustraliansAmerican Indians

3. Or we can use other physical traits. Example: Fingerprint patterns.

Race Includes people from:

Looped race: EuropeansAfricans

East Asians

Whorled race: Mongolians Aboriginal Australians

Arched race: Khoisan Africans Central Europeans

E. So what’s wrong with humans?! Why is it so difficult to form

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Is everyone in these populations exclusively Lactase-positive or Lactase-negative?

Does everyone in these populations exclusively have looped, whorled, or arched races?

Note: Arched can be further separated.

scientifically valid ‘races’ in humans compared to many other organisms?

1. Human populations have always interbred. Gene exchange has always occurred.

a. Interbreeding between neighboring populations.

b. Migration to distant populations.

2. Even secluded groups have not been isolated long enough to disconnect their genetics from other populations. Not enough genetic change has occurred to create ‘races’.

F. So why are the traditional human racial groupings used?

1.

2.

3. What does separate us?

“Traditional ‘racial’ designations in humans are not bounded, discrete categories but are fluid, socially defined constructs that have some poorly understood correlations with various biological elements and health outcomes.”

IV. Human Genome Project

The Human Genome Project seeks to find variation (differences) between people without value judgments of individual or group worth. There are many worthwhile reasons for finding these variations.

A. One of the main goals of the HGP is to benefit humans medically. A helpful discovery has been that different people have altered responses to drugs due to genetic variations.

Pharmacogenomics

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B. Concerns about the Human Genome Project

1. Exploitation of third world peoples.

a. Profitsb. Patentsc. Informed consent

2. Using genetics to devalue specific races.

Example: Hypertension study: Randall Tackett (U. of Georgia)

a. Results: Black men’s veins don’t return to normal as quickly after being exposed to chemicals that cause them to constrict.

“This is the first direct demonstration that there are racial differences at the level of the vasculature.”

b. What didn’t he emphasize?

1) Only 22 men from Georgia were tested.2) Native Africans have very low rates of hypertension.3) Finns and Russians have notoriously high rates of hypertension.

“What you make of race depends on what the question is. And who wants to know.” (Shreeve, 1994).

Lecture Summary

1. Humans are difficult to classify beyond the species level.

a. Although people do differ, human groups do not differ enough genetically to form ‘races’. Races do not biologically exist in humans.

1) Human populations have always interbred.

2) Thus, there are individuals in every traditional human race with ‘alleles’ found in other traditional racial groups.

3) Our separations haven’t been long enough to form subspecies.

b. Genetically, variations among groups are better considered in dynamic populations (groups of individuals living in the same area or with common ancestry), not large groupings of people bundled into a few ‘races’.

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2. Traditional racial groupings primarily are based on ‘appearance’. Appearance-based characteristics in humans are 1) not tightly defined, 2) geographically, often are found on a continuum, 3) are not easily used, and 4) using these characteristics many people are unclassifiable. Therefore, traditional racial groupings are not biologically valid.

3. Traditional racial groupings are highly subjective. Therefore, they are open to bias and value judgments of individual and group worth. This provides an excuse to devalue certain cultures, religions, ethnicities, and other groups. Appearance-based traits have not been linked to other traits such as intelligence, creativity, and athletic performance.

4. The Human Genome Project seeks to find variation (differences) between people without value judgments. However, the project leaders realize the potential problems. Three to five percent of the HGP budget has gone toward education and outreach.

5. The NHGC (National Human Genome Center) is located at Howard University.NHGC Goal:The goal of the NHGC is to bring multicultural perspectives and resources to an understanding of human genome variation and its implications for disease prevention and health promotion.http://www.genomecenter.howard.edu/

Primary Works Consulted for this Lecture Topic

Royal, C. and Dunston, G.M. 2004. Nature Genetics. http://www.nature.com/ng/journal/v36/n11s/full/ng1454.html

Lewis, R. Feb. 18, 2002. Race and the Clinic: Good Science? The Scientist.Marks, J. Dec. 1994. Black White Other. Natural History, pp. 32-35. Shreeve, J. Nov. 1994. Terms of Estrangement. Discover, pp. 56-63.RACE The Power of an Illusion http://www.pbs.org/race/000_General/000_00-Home.htmSkin Color http://www.ryanphotographic.com/skincolor.htmShades of Brown: The Law of Skin Color: http://www.law.duke.edu/journals/dlj/articles/DLJ49P1487.htmEthnicity, Race, Racism http://www.austin.cc.tx.us/amaldona/id22.html

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V. PBS The Power of an Illusion website

http://www.pbs.org/race/002_SortingPeople/002_00-home.htm

A. Sorting People (in-class)

There’s less—and more—to race than meets the eye.

1. Begin Sorting: Who goes where?2. Explore Traits3. Click on Human Diversity and take the Human Diversity Quiz 4. Click on What is Race and read 1-10

B. RACE The Power of an Illusion (Episode 1 The Difference Between Us)

Students: Read the following before the viewing RACE The Power of an Illusion (Episode 1 The Difference Between Us).

Dear Viewer,

Race is one topic where we all think we’re experts. Yet ask 10 people to define race or name "the races," and you’re likely to get 10 different answers. Few issues are characterized by more contradictory assumptions and myths, each voiced with absolute certainty.

In producing this series, we felt it was important to go back to first principles and ask, What is this thing called "race"? - a question so basic it is rarely raised. What we discovered isthat most of our common assumptions about race – for instance, that the world’s peoplecan be divided biologically along racial lines – are wrong. Yet the consequences of racismare very real.

How do we make sense of these two seeming contradictions? Our hope is that this series can help us all navigate through our myths and misconceptions, and scrutinize some ofthe assumptions we take for granted. In that sense, the real subject of the film is not somuch race but the viewer, or more precisely, the notions about race we all hold.

— Larry Adelman, Executive Producer

PRINT The Power of An Illusion DVD questions ON THE LAST PAGE OF THIS DOCUMENT. While/after viewing the DVD, answer the questions on the last page of this document.

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RACE and GENETICSPost-Test

1. List the classification hierarchy taxa in the correct order.

2. What are some of the characteristics of all members of the species Homo sapiens?

3. What is the basis for classifying sexually reproducing organisms into the same species?

4. Describe the ‘subjective’ nature of scientific classification (for any organism).

5. Explain how populations of organisms (any species) accumulate differences over time.

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6. Who was the first person to classify humans into four primary varieties? What were these varieties?

7. Describe Blumenbach’s classification system of humans. What effect did his classification have on human societies? Why?

8. In order to be scientifically valid, a subspecies classification must follow what ‘rules’?

9. Why can’t these ‘rules’ be followed with respect to human racial classification? In other words, why is it so difficult to classify humans beyond the species level?

10. What types of characteristics have been used for traditional racial groupings?

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11. Describe the biology and inheritance of skin color. Include advantages of dark and light skin in high UV and low UV environments, respectively.

12. Why is skin color (or any appearance-based characteristic) a bad choice for grouping humans? Why have appearance-based characteristics been used by humans for ‘racial’ classifications?

13. Why don’t resistance to disease, lactose intolerance and fingerprint patterns form tightly defined groups of humans?

14. Give an example of an ‘unclassifiable’ group of people, and describe why this group is unclassifiable based on traditional racial groupings.

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15. What does separate the ‘races’?

16. How do geneticists prefer to study humans? Why?

17. Give an example of how the human genome project has been used to provide medical information.

18. Describe concerns associated with the Human Genome Project.

19. From a biological perspective, are human ‘races’ meaningful and useful? Why or why not.

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PBS The Power of An Illusion DVD QuestionsANSWERS MUST BE TYPED UNDER THE QUESTIONS.

Name:

A. At the beginning of the film, the students are asked to predict whom they will be most like when they compare their DNA samples. How did the results compare with your expectations? Did you share the students’ surprise? If so, why?

B. What are some reasons why some traits have been traditionally used to classify, but not others?

C. What is the difference between a biological and a social view of race?

D. How is ancestry different from race?

E. Describe some views concerning race and genetic or biologically based differences throughout history. How and why did these views and the explanations for these views change over the years?

F. Athletics is one arena where talking about ideas of inborn racial differences remains common. Why do you think some populations or groups seem to dominate certain sports but not others? What does it mean that the groups that dominate those sports have changed over time?

G. Anthropologist Alan Goodman says that “to understand why the idea of race is abiological myth requires a major paradigm shift.” Do you agree? Did the film presentanything that shifted your thinking in a major way? If so, what? Is it difficult to make thisshift? Why?

H. Review your answers on page 1 of the lecture guide. Did the film change or challenge any of your assumptions about race? If so, which ones? Has your definition of race changed? If so, how?

I. Two weeks from now, what will you most remember from the film and why?

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