Does Race Exist?
Current Issues in Biology, Volume 2
Scientific American
PowerPoint® Lectures
Lectures by April Lynch
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Does Race Exist?
Concept Review
• Most common definitions of race are based on external
features, such as skin color.
• But research reveals that races are not genetically discrete
groups.
• Genetic differences can be used, however, to group
populations for purposes such as medical relevance.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Does Race Exist?
Concept Review
• The genes of two people of the same “race” can be very
different.
• Conversely, two people of different “races” can share
more in common genetically than two individuals of the
same “race.”
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Does Race Exist?
Concept Review
• Scientists can sometimes use small genetic differences
called polymorphisms to sort most large populations
according to their ancestral geographic origin.
• One such polymorphism-based study identified five different
groups with distinct geographic origins, including subSaharan Africans, Europeans, and East Asians.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Does Race Exist?
Concept Review
• The study was based on comparisons of short pieces of
DNA called Alu polymorphisms.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Does Race Exist?
Concept Review
• These variations arose due to ancestral geographic isolation.
• These differences sometimes have medical implications.
People with a particular variation may be more prone to a
certain disease or have a unique response to a drug.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Does Race Exist?
Concept Review
• But scientists and doctors are still debating the full medical
utility of genetic variations.
• It is not yet clear how medically significant some differences
may be.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Does Race Exist?
Testing Your Comprehension
According to scientists, which of these reliably defines race?
a) culture
b) skin color
c) geographic origin
d) none of the above
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Does Race Exist?
Testing Your Comprehension
According to scientists, which of these reliably defines race?
d) none of the above
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Does Race Exist?
Testing Your Comprehension
How do geneticists determine the degree of relatedness
among human groups?
a) variations in the genes for skin color
b) DNA polymorphisms
c) variation in the chemistry of DNA bases
d) none of the above
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Does Race Exist?
Testing Your Comprehension
How do geneticists determine the degree of relatedness
among human groups?
b) DNA polymorphisms
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Does Race Exist?
Testing Your Comprehension
Geneticists study the history of populations and the effect of
natural selection by
a) interviewing people about their ancestry.
b) analyzing historical records and ancient burial sites.
c) studying polymorphisms across populations.
d) comparing the number of polymorphisms in a population.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Does Race Exist?
Testing Your Comprehension
Geneticists study the history of populations and the effect of
natural selection by
c) studying polymorphisms across populations.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Does Race Exist?
Testing Your Comprehension
At present, what factor is the major limiter in using genetic
testing as a broad screening tool?
a) concerns about privacy and consent
b) validity of the information
c) high cost of the screening
d) all of the above
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Does Race Exist?
Testing Your Comprehension
At present, what factor is the major limiter in using genetic
testing as a broad screening tool?
d) all of the above
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
Does Race Exist?
Biology and Science
Researchers have argued that outward signs of race are
not adequate for distinguishing a person’s genetic
characteristics. Their findings support efforts to heal racial
divides.
Strongly
Agree
A.
B.
C.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings
D.
E.
Strongly
Disagree
Does Race Exist?
Thinking About Science
Some scientists now say that racial information has no valid
place in medical research. Others say it does, as race is still
a powerful social force. Describe at least one scientific
claim that can be used by those on each side of the debate.
Copyright © 2006 Pearson Education, Inc. publishing as Benjamin Cummings