Download crosses. - Aurora City Schools

Intro to Genetics
Chapter 11.1-11.3
p. 306-322
Chapter 11 and 14 Genetics 2010
1
Key
terms
• Genetics
•
•
•
•
•
•
•
•
•
•
•
•
•
Fertilization
Trait
Hybrid
Gene
Allele
Principle of dominance
Segregation
Gamete
Probability
Homozygous
Heterozygous
Phenotype
Genotype
•
•
•
•
•
•
Punnett square
Independent assortment
Incomplete dominance
Codominance
Multiple allele
Polygenic trait
Chapter 11 and 14 Genetics 2010
2
Review?
Heredity: What is a gene?
is a segment of DNA that is located in a
chromosome and that codes for a
specific trait
Crossing over: How does it contribute to
the physical differences between
siblings?
exchange of genetic material between
homologous chromosomes genetic
recombination
Chapter 11 and 14 Genetics 2010
3
THINK ABOUT IT
What is an inheritance?
It is something we each receive from our parents—a contribution that
determines our blood type, the color of our hair, and so much more.
What kind of inheritance makes a person’s face round or hair curly
Where does an organism get its unique characteristics
 An individual’s characteristics are determined by factors that are
passed from one parental generation to the next.
 The delivery of characteristics from parent to offspring is called
heredity.
 The scientific study of heredity, known as genetics, is the key to
understanding what makes each organism unique
Chapter 11 and 14 Genetics 2010
4
leucism
• This alligator is one of 18 white alligators discovered
southwest of New Orleans in 1987 by a fisherman.
• How is he different from alligators you have seen?
• It is not a different species and it is not albino.
• Albinos have off-white or yellowish skin and colorless
irises or look pink
• This alligator is more rare than one that would be an
albino.
Chapter 11 and 14 Genetics 2010
5
Need to know!!
1. Describe how Mendel was able to control his
pea plants were pollinated.
2. Describe the steps in Mendel's experiments on
true-breeding garden peas.
3. Distinguish between dominant and recessive
traits.
4. State two laws of heredity that were developed
from Mendel’s work
5. Describe how Mendel's results can be
explained by scientific knowledge of genes and
chromosomes
Chapter 11 and 14 Genetics 2010
6
Mendel’s Legacy
• Genetics is the field of biology devoted to
understanding how characteristics or traits
are transmitted from parents to offspring.
Genetics was founded with the work of
Gregor Johann Mendel.
Chapter 11 and 14 Genetics 2010
7
Gregor Mendel1822-1884
• Studied science and mathematics (statistics)
• Studied heredity (characteristics from parents to
offspring)
• Studied garden peas, characteristics, flower
color, height, pod appearance, texture or traits
• A trait is a specific characteristic of an individual,
such as seed color or plant height, and may vary
from one individual to another.
Led to basic principles of genetics
•
•
Web demo holt
http://my.hrw.com/index.jsp
Chapter 11 and 14 Genetics 2010
8
Mendel’s Methods
•
•
Controlled how plants were pollinated
Or how the pollen grains produced in the
male reproductive parts of a flower
(anthers/stamen) to the female
reproductive parts of the flower
(stigma/pistle)
Two types:
1. Self- pollination
2. Cross pollination
Chapter 11 and 14 Genetics 2010
9
Chapter 11 and 14 Genetics 2010
10
Mendel’s Methods cont:
1. Self- pollination- occurs when pollen is
transferred from the anthers of a flower to the
stigma of either that flower or another flower
on the same plant.
*Can be prevented if remove male parts
2. Cross-pollination- occurs between flowers of
two plants, can be specific for traits
*Mendel used this method to study plants
Web demo holt
Chapter 11 and 14 Genetics 2010
11
Mendel’s Experiments
• True-breeding or pure for a trait will produce offspring
with a trait of self-pollinate
Ex: yellow pod x yellow pod = yellow pod
• Cross pollinated pairs of plants that were true-breeding
for one trait and then another
• True-breeding parents were P generation
• First generations F1
• Second generations F2
• Mendel’s crosses
Web demo holt
Chapter 11 and 14 Genetics 2010
12
Chapter 11 and 14 Genetics 2010
13
Genes and Alleles
From these results, Mendel drew two conclusions. His first conclusion
formed the basis of our current understanding of inheritance.
An individual’s characteristics are determined by factors that are passed
from one parental generation to the next.
Scientists call the factors that are passed from parent to offspring genes.
Each of the traits Mendel studied was controlled by one gene that occurred
in two contrasting varieties.
These gene variations produced different expressions, or forms, of each
trait.
The different forms of a gene are called alleles
Chapter 11 and 14 Genetics 2010
14
Dominant and Recessive Traits
Mendel’s second conclusion is called the principle of dominance. This
principle states that some alleles are dominant and others are recessive.
An organism with at least one dominant allele for a particular form of a trait
will exhibit that form of the trait.
An organism with a recessive allele for a particular form of a trait will exhibit
that form only when the dominant allele for the trait is not present.
Chapter 11 and 14 Genetics 2010
15
Segregation
How are different forms of a gene
distributed to offspring?
During gamete formation, the
alleles for each gene segregate
from each other, so that each
gamete carries only one allele for
each gene.
Chapter 11 and 14 Genetics 2010
16
Results and conclusions
• Pair of factors (genes) controlled for traits
• Only one trait was visible in F1 generation
(dominant factor)
• Traits appeared in the F2 generations in
3:1 ratio (recessive factor)
• Law of segregation- pair of factors are
separated during formation of gametes or
meiosis
• Law of Independent Assortment- factors
separate independently of one another
during the formation of gametes (meiosis)
Chapter 11 and 14 Genetics 2010
17
Chapter 11 and 14 Genetics 2010
18
Chapter 11 and 14 Genetics 2010
19
Lesson Overview
11.2 Applying Mendel’s
Principles
Chapter 11 and 14 Genetics 2010
20
Key questions?
• Differentiate between the genotype and the phenotype
of an organism
• Explain how probability is used to predict the results of
genetic crosses
• Use a Punnett square to predict the results of a
monohybrid and dihybrid genetic crosses
• Explain how a testcross is used to show the genotype of
an individual whose phenotype expresses the dominant
trait
• Differentiate a monohybrid cross from a dihybrid cross
Chapter 11 and 14 Genetics 2010
21
Genetic Crosses
• Today, geneticists rely on Mendel’s work
to predict the likely outcome of genetic
crosses. In this section you will learn how
to predict the probable genetic makeup
and appearance of offspring resulting from
specified crosses.
Chapter 11 and 14 Genetics 2010
22
Probability and Punnett Squares
How can we use probability to predict traits?
Punnett squares use mathematical probability to help predict the genotype
and phenotype combinations in genetic crosses.
Mendel realized that the principles of probability could be used to explain
the results of his genetic crosses.
Probability is the likelihood that a particular event will occur.
Chapter 11 and 14 Genetics 2010
23
Probability and Punnett Squares
For example, there are two possible outcomes of a coin flip: The coin
may land either heads up or tails up.
The chance, or probability, of either outcome is equal. Therefore, the
probability that a single coin flip will land heads up is 1 chance in 2. This
amounts to 1/2, or 50 percent
If you flip a coin three times in a row, what is the probability that it will land
heads up every time?
Each coin flip is an independent event, with a one chance in two
probability of landing heads up.
Therefore, the probability of flipping three heads in a row is:
1/2 × 1/2 × 1/2 = 1/8
Past outcomes do not affect future ones. Just because you’ve flipped
3 heads in a row does not mean that you’re more likely to have a
coin land tails up on the next flip
.
Chapter 11 and 14 Genetics 2010
24
Probability
• The likelihood that a specific event will
occur.
• Can be expressed as a:
– Decimal
– Percentage
– Fraction
Probability=(# of time event expected to
happen)/ (# of time it could happen)
Chapter 11 and 14 Genetics 2010
25
Chapter 11 and 14 Genetics 2010
26
Using Segregation to Predict Outcomes
The way in which alleles
segregate during gamete
formation is every bit as random
as a coin flip.
Therefore, the principles of
probability can be used to
predict the outcomes of genetic
crosses.
Chapter 11 and 14 Genetics 2010
27
Terms
1. Genotype- genetic makeup, alleles that
are inherited from parents (PP, Pp, pp)
2. Phenotype- physical appearance (color,
height), does not always resemble
genotype due to environment factors
3. Homozygous- alleles are the same, can
be dominant (PP) or recessive (pp)
4. Heterozygous- alleles are different (Pp)
Chapter 11 and 14 Genetics 2010
28
More terms
1. Monohybrid cross- cross with only one
characteristic, offspring are monohybrids
2. Punnett square- used to do monohybrid
crosses, used to predict outcomes
3. Genotypic ratio- ratio of genotypes that
appear (1BB: 2Bb: 1bb)
4. Phenotypic ratio- ratio of phenotypes
that appear (3 brown : 1 black)
5. Test cross- unknown organism is
crosses with a homozygous recessive
Chapter 11 and 14 Genetics 2010
29
How To Make a Punnett Square for a OneFactor Cross
Write the genotypes of the two organisms that will serve as parents in a
cross.
In this example we will cross a male and female osprey that are
heterozygous for large beaks. They each have genotypes of Bb.
Bb and Bb
Chapter 11 and 14 Genetics 2010
30
How To Make a Punnett Square
Draw a table with enough spaces for each pair of gametes from each
parent.
Enter the genotypes of the gametes produced by both parents on the
top and left sides of the table.
Chapter 11 and 14 Genetics 2010
31
How To Make a Punnett Square
Fill in the table by combining the gametes’ genotypes.
Chapter 11 and 14 Genetics 2010
32
How To Make a Punnett Square
Determine the genotypes and phenotypes of each offspring.
Calculate the percentage of each. In this example, three fourths of the
chicks will have large beaks, but only one in two will be heterozygous.
Chapter 11 and 14 Genetics 2010
33
Chapter 11 and 14 Genetics 2010
34
Types of crosses:
A. Homozygous x Homozygous (PP x pp)
B. Homozygous x Heterozygous (PP x Pp)
(complete dominance)
C. Heterozygous x Heterozygous (Pp x Pp)
D. Test cross (pp x P_)
Chapter 11 and 14 Genetics 2010
35
Types of crosses:
E. Incomplete
dominance- F1
offspring has a
phenotype in
between that of
parents, Cross a
white (rr) flower with
a Red flower (RR)=
pink flower (Rr)
Chapter 11 and 14 Genetics 2010
36
Types of crosses
F. Codominance-both
alleles fro a gene
are expressed on a
heterozygous
offspring, neither
trait is dominant or
recessive, blood
types
Chapter 11 and 14 Genetics 2010
37
Independent Assortment
How do alleles segregate when more than one gene is involved?
The principle of independent assortment states that genes for different
traits can segregate independently during the formation of gametes.
Mendel wondered if the segregation of one pair of alleles affects another pair.
Mendel performed an experiment that followed two different genes as they
passed from one generation to the next.
Because it involves two different genes, Mendel’s experiment is known as
a two-factor, or dihybrid, cross. Single-gene crosses are monohybrid
crosses.
Chapter 11 and 14 Genetics 2010
38
Dihybrid crosses
•
Two characteristics are tracked, results
are dihybrid
Types of crosses( 4 x4 box)
1. Homozygous RRYY x Homozygous rryy
2. Heterozygous RrYy x Heterozygous
RrYy (9:3:3:1)
Chapter 11 and 14 Genetics 2010
39
Chapter 11 and 14 Genetics 2010
40
A Summary of Mendel’s Principles
What did Mendel contribute to our understanding of genetics?
Mendel’s principles of heredity, observed through patterns of
inheritance, form the basis of modern genetics
At the beginning of the 1900s, American geneticist Thomas Hunt
Morgan decided to use the common fruit fly as a model
organism in his genetics experiments.
The fruit fly was an ideal organism for genetics because it could
produce plenty of offspring, and it did so quickly in the laboratory.
Before long, Morgan and other biologists had tested every one of
Mendel’s principles and learned that they applied not just to pea
plants but to other organisms as well.
The basic principles of Mendelian genetics can be used to study the
inheritance of human traits and to calculate the probability of certain
traits appearing in the next generation.
Chapter 11 and 14 Genetics 2010
41
Human Heredity
Chapter 14
p. 390-410
Chapter 11 and 14 Genetics 2010
42
A little Q and A
Can you ID some parts to the
chromosomes
- centromere, chromatids
How many chromosomes are found in the
normal human genome
46 (2n)
Each chromosome contains many genes
Chapter 11 and 14 Genetics 2010
43
A little Q and A
Differences between dominant and
recessive
dominance: when an allele that masks
the presence of another allele for the
same characteristic
Recessive: when an allele that is masked
by the presence of another allele for that
same characteristic
Can you give examples?
Chapter 11 and 14 Genetics 2010
44
Objectives
• Distinguish between sex chromosomes
and autosomes
• Explain the role of sex chromosomes in
sex determination
• Describe how an X or Y linked gene
affects the inheritance of genes in linkage
groups
• Distinguish between chromosomes
mutations and gene mutations
Chapter 11 and 14 Genetics 2010
45
Chromosomes and Inheritance
• Francis Collins and his lab group discovered
the gene responsible for Cystic Fibrosis. CS is
often fatal genetic disorder. Thick, sticky
mucus builds up and blocks ducts in the
pancreas and intestines and causes difficulty
in breathing.
• In this chapter we will learn how diseases and
characteristics are inherited and expressed.
Chapter 11 and 14 Genetics 2010
46
Chromosomes
• 1900s Thomas Hunt Morgan
experimented with Drosophila
melanogaster
• Observed that they had 4pairs of
chromosomes
• 3 pairs were identical in male and female
• The fourth pairs was the sex
chromosomes XX female, XY male
Chapter 11 and 14 Genetics 2010
47
Sex chromosomes and
autosomes
• Sex chromosomes- contain genes that
determine the sex (gender) of an individual
• Autosomes- non sex chromosomes
Sex determinationSex chromosomes pair during meiosis
Child will always receive a x chromosome from the
mother
SRY gene- sex-determining Region Y, if have this
gene hormones are released and testes form
and if not ovaries form
Chapter 11 and 14 Genetics 2010
48
Can you determine the probability
of the sex of the child?
1. Cross a Male and a Female
XY x XX
2. Set up your punnett square
3. What are your ratios?
4. Who determines the sex of the child?
Chapter 11 and 14 Genetics 2010
49
Sex Chromosomes
This Punnett square illustrates
why males and females are
born in a roughly 50 : 50 ratio.
All human egg cells carry a
single X chromosome (23,X).
However, half of all sperm
cells carry an X chromosome
(23,X) and half carry a Y
chromosome (23,Y).
This ensures that just about
half the zygotes will be males
and half will be females.
Chapter 11 and 14 Genetics 2010
50
Sex Chromosomes
More than 1200 genes are found
on the X chromosome, some of
which are shown.
The human Y chromosome is
much smaller than the X
chromosome and contains only
about 140 genes, most of which
are associated with male sex
determination and sperm
development.
Chapter 11 and 14 Genetics 2010
51
Effects of Gene location
• Sex-linked genes and traits
some genes are located on the sex chromosomes
Ex: in DM the gene for eye color is located on the X
chromosome, Y chromosome lacks this gene
Do this cross:
1. (p1) cross an X(R ) X(R ) female red eye with an X(r )
Y male white eye, what is the F1 generation?
Now take two from the F1 and cross them and see what
you get?
Chapter 11 and 14 Genetics 2010
52
Sex- linked genes and traits
• The results of these experiments showed
Morgan not only genes reside on
chromosomes but that red eye color is
located on the X chromosome
• Genes can be both x linked or y linked
• Sex linked trait –is coded for by an allele
on a sex chromosome
Chapter 11 and 14 Genetics 2010
53
Linked Genes
• Pairs of genes that tend to be inherited
together
• Genes are linked because they are found
on the same chromosome
• Crossing over during meiosis does not
create new genes or delete old ones, just
rearranges alleles
• Linkage group- set of linked genes
Chapter 11 and 14 Genetics 2010
54
Chromosome mapping
• The farther apart the genes are located on
a chromosome, increases the chance of
cross-over
• Chromosome map- diagram that shows
the linear order of genes on a
chromosome
• Map unit- frequency of crossing-over
• Today modern technology has made it
easier to map genes (human genome
project)
Chapter 11 and 14 Genetics 2010
55
Chapter 11 and 14 Genetics 2010
56
Mutations
• Change in the nucleotide-base sequence of a
gene or DNA molecule
• Germ-cell: occurs in an organism’s gametes,
can be passed on to an offspring
• Somatic-cell: body cell and can affect the
organism, skin cancer, leukemia, can not be
inherited!!
• Lethal mutations- cause death before birth
• Can mutations be beneficial to the individual?
Chapter 11 and 14 Genetics 2010
57
Chromosome Mutations
Two ways
1. change in structure of chromosome
2. adding or loosing a chromosome
• Deletion- loss of a piecd of a chromosome due to
breakage
• Inversion- segments breaks off, flips around and
reattaches
• Translocation- breaks off and reattaches to non
homologous chromosome
• Nondisjunction- chromosome fails to separate from its
homologous during meiosis, get and extra copy (trisomy
21)
Chapter 11 and 14 Genetics 2010
58
Gene Mutations
• Point mutations- substitution, addition, or
removal of single nucleotide
• Substitution- one nucleotide replaces
another
• Frameshift mutation- it just shifts downcreates new amino acids
• Insertion mutations- addition of a gene
and framshift occurs
• ATCGA
Chapter 11 and 14 Genetics 2010
59
Chapter 11 and 14 Genetics 2010
60
Chapter 11 and 14 Genetics 2010
61
Inheritance patterns and human
genetics
Human Genetics
12.2
241-249
Chapter 11 and 14 Genetics 2010
62
objectives
• Analyze pedigrees to determine how genetic
traits and genetic disorders are inherited
• Summarize the different patterns of inheritance
seen in genetic traits and genetic disorders
• Explain the inheritance of ABO blood groups
• Compare sex-linked traits with sex-influenced
traits
• Explain how geneticists can detect and treat
genetic disorders
Chapter 11 and 14 Genetics 2010
63
Human Genetics
• This section investigates how genetics
analyze genetic data from families to track
the inheritance of human genes. It also
explores the genetic and environmental
factors that influence human genetic traits
and disorders, and discusses how
geneticists detect and treat human genetic
disorders.
Chapter 11 and 14 Genetics 2010
64
Inheritance of traits
Why do geneticists study human genetic traits?
To trace genetic diseases from generation to
generation
Study the phenotypes of family members in
a pedigree
Pedigrees- diagram that shows how a trait is
inherited over several generations
Chapter 11 and 14 Genetics 2010
65
This will be on OGT
Chapter 11 and 14 Genetics 2010
66
Honors:Chapter 9
Patterns of Inheritance
67
Honors:Chapter 9
Patterns of Inheritance
68
Patterns of inheritance-
Expression of genes over generations
• Autosomal traits- appear in both sexes equally
• Sex-linked- tend to see only in males, most are
recessive
• Carriers- they have one copy of the allele but do
not have the disease, they do not express the
disease but can pass it to offspring
-Most are born from normal parents
(phenotypically normal) who carries the
recessive gene (allele)
-Inbreeding- increases the chances of expression
of recessive traits
Chapter 11 and 14 Genetics 2010
69
inherited disorders
Dominant Disorders- only need one trait
1. achondroplasis- dwarfism
2. Huntington’s – mental deterioration,
middle ages
Less likely to be passes if deadly – don’t
reproduce
Honors:Chapter 9
Patterns of Inheritance
70
Genetic traits and disorders
• Genetic disorders are diseases that have
genetic origin
• Polygenic inheritance- characteristics are
influenced by many genes
– Skin color (3-6 genes), eye color, height
 Complex characters-influenced strongly
both by the environment and by genes
 Skin color is both polygenic and complex,
cancers
Chapter 11 and 14 Genetics 2010
71
Honors:Chapter 9
Patterns of Inheritance
72
single gene may affect many phenotypic
characteristics
• Pleiotropy- genes influence multiple
characteristics
example
• Fig 9.14 sickle-cell, 1 thing  chain events
• coloration pattern and crossed eyes of Siamese
cats, which are both caused by the same allele.
These unrelated characters are caused by the
same protein produced by the same allele.
• gene that causes pigment color in rats. White
rats also have very sensitive eyes and often
become blind.
Honors:Chapter 9
Patterns of Inheritance
73
Blood Types - Multiple Alleles and
Codominance
• In humans, there are four blood types
(phenotypes): A, B, AB, and O
• Blood type is controlled by three alleles. A, B, O
• O is recessive, two O alleles must be present for
the person to have type O blood
• A and B are codominant. If a person receives an
A allele and a B allele, their blood type is type
AB
• Crosses involving blood type often use an I to
denote the alleles - see chart.
Honors:Chapter 9
Patterns of Inheritance
74
Multiple alleles
• Having more than 3 alleles
• Blood type ABO, codominance (fig 12.12)
–
–
–
–
A
B
AB
O
Chapter 11 and 14 Genetics 2010
75
Honors:Chapter 9
Patterns of Inheritance
76
Codominant and Multiple Alleles
This table shows the relationship between genotype and phenotype for the
ABO blood group.
It also shows which blood types can safely be transfused into people with
other blood types.
Alleles IA and IB are codominant. They produce molecules known as
antigens on the surface of red blood cells.
Individuals with alleles IA and IB produce both A and B antigens, making
them blood type AB.
Chapter 11 and 14 Genetics 2010
77
More genetic traits
Incomplete dominance- trait hair, and curly
hair parents have a wavy hair child
X- linked- carried on the x chromosomes,
color blindness is a recessive x linked
Sex-influenced traits- dependent on male
or female, baldness, have same genotype,
tend to be autosomal, hormones play role
Single-allele traits- 200 dominate alleles,
Huntington's (HD)autosomal, pass genes
before they are aware have it (30-40ys)
Chapter 11 and 14 Genetics 2010
78
Detecting Genetic Disease
• If you have family history see testing
• Genetic screening- Karyotype, blood
tests,
• Detect 200 disorders in the fetus by
amniocentesis
• Chorionic villi sampling- take cells from
zygote between the mothers uterus and
placenta between 8-10wks
Chapter 11 and 14 Genetics 2010
79
Karyotype
Chapter 11 and 14 Genetics 2010
80
Questions about a Karyotype?
1. What term do we use to describe the pair
of chromosomes?
2. How are the chromosomes that make up
each number pair similar?
3. What chromosomes are autosomes?
4. Which are sex chromosomes?
5. Can you explain any abnormalities?
Chapter 11 and 14 Genetics 2010
81
Abnormal number of sex
chromosomes
• XXY
Klinefelter - male sex organs, testes
small, individual is sterile, breast enlargement,
other female characteristics, normal intelligence
(meiosis in egg/sperm)
• XYY
normal male- can be taller, (meiosis in
sperm)
• XXXnormal female –(meiosis egg/ sperm)
• XO Turner syndrome (female, egg/sperm),
sterile, short stature, artificial estrogen
Honors Biology notesChapter 8 2008
82
Honors Biology notesChapter 8 2008
83
Genetic Counseling
• Process of informing a person about the
parents or potential new Childs genetic
makeup
• Problems that could affect the offspring
• Predict the probability that offspring will be
healthy or have a genetic disorder
• Risk factors
Chapter 11 and 14 Genetics 2010
84
Treating genetic diseases
• PKU- lacks the enzyme, causes mental
retardation, strict foods, no diet soda,
blood tests
• CF- pounding on the back 45min sessions
Gene therapy- replacing the defective gene
Somatic cell gene therapy
Germ cell gene therapy- eggs and sperm
Is this ethical- how does this affect the next
generation???
Chapter 11 and 14 Genetics 2010
85
Environment play a role
• Combination of heredity and environment
List some examples
1. mother nature, wind, sun,
2. nutrition, exercise, sun
3. nature vs nurture
genetic testing- can detect disease-causing
alleles
Honors:Chapter 9
Patterns of Inheritance
86
What We Have Learned
In June 2000 scientists
announced that a working copy of
the human genome was
complete.
The first details appeared in the
February 2001 issues of the
journals Nature and Science.
The full reference sequence was
completed in April 2003, marking
the end of the Human Genome
Project—two years ahead of the
original schedule.
Chapter 11 and 14 Genetics 2010
87
What We Have Learned
The Human Genome Project found that the human genome in its
haploid form contains 3 billion nucleotide bases.
Only about 2 percent of our genome encodes instructions for the
synthesis of proteins, and many chromosomes contain large areas with
very few genes.
Chapter 11 and 14 Genetics 2010
88
What We Have Learned
As much as half of our genome is made up of DNA sequences from
viruses and other genetic elements within human chromosomes.
This chart compares the human genome with other organisms.
Chapter 11 and 14 Genetics 2010
89
What We Have Learned
More than 40% of our proteins are similar to proteins in organisms such
as fruit flies, worms, and yeast.
This chart compares the human genome with other organisms.
Chapter 11 and 14 Genetics 2010
90
What We Have Learned
The Human Genome Project pinpointed genes and associated particular
sequences in those genes with numerous diseases and disorders.
It also identified about three million locations where single-base DNA
differences occur in humans, which may help us find DNA sequences
associated with diabetes, cancer, and other health problems.
The Human Genome Project also transferred important new technologies to
the private sector, including agriculture and medicine.
The project catalyzed the U.S. biotechnology industry and fostered the
development of new medical applications.
Chapter 11 and 14 Genetics 2010
91
New Questions
The Human Genome Project worked to identify and address ethical, legal,
and social issues surrounding the availability of human genome data and its
powerful new technologies.
For example, who owns and controls genetic information? Is genetic privacy
different from medical privacy? Who should have access to personal genetic
information, and how will it be used?
In May 2008, President George W. Bush signed into law the Genetic
Information Nondiscrimination Act, which prohibits U.S. insurance
companies and employers from discriminating on the basis of information
derived from genetic tests. Other protective laws may soon follow.
Chapter 11 and 14 Genetics 2010
92
What’s Next?
The 1000 Genomes Project, launched in 2008, will study the genomes of 1000 people
in an effort to produce a detailed catalogue of human variation.
Data from the project will be used in future studies of development and disease, and
may lead to successful research on new drugs and therapies to save human lives and
preserve health.
In addition, many more sequencing projects are under way and an ever-growing
database of information from microbial, animal, and plant genomes is expected.
Perhaps the most important challenge that lies ahead is to understand how all the
“parts” of cells—genes, proteins, and many other molecules—work together to create
complex living organisms.
Chapter 11 and 14 Genetics 2010
93