12.1 section objectives – page 309 1. which of these traits do you have? 2. how would knowing your...

1. Which of these traits do you have?

2. How would knowing your parents’ phenotypes help you determine your genotype?

Genetics

Patterns of Heredity and Human Genetics

Mendelian Inheritance of Human Traits

• A family tree traces a family name and various family members through successive generations.

• Through a family tree, you can identify the relationships among your cousins, aunts, uncles, grandparents, and great-grandparents.

Making a PedigreeMaking a Pedigree

• Pedigree: a graphic representation of genetic inheritance

• It is a diagram made up of a set of symbols that identify males and females, individuals affected by the trait being studied, and family relationships.

Pedigrees illustrate inheritancePedigrees illustrate inheritance

Pedigrees illustrate

inheritance

Pedigrees illustrate

inheritance

Male

Female

Affected male

Affected female

Mating

Parents

Siblings

Known heterozygotes for recessive allele

Death

• In a pedigree, a circle represents a female; a square represents a male.

Pedigrees illustrate inheritance


Female Male

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• Highlighted circles and squares represent individuals showing the trait being studied.

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• Circles and squares that are not highlighted designate individuals that do not show the trait.

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• A half-shaded circle or square represents a carrier, a heterozygous individual.


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Pedigrees illustrate inheritancePedigrees illustrate inheritance• A horizontal line

connecting a circle and a square indicates that the individuals are parents, and a vertical line connects parents with their offspring.

Pedigrees illustrate inheritancePedigrees illustrate inheritance• Each horizontal

row of circles and squares in a pedigree designates a generation, with the most recent generation shown at the bottom.

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• The generations are identified in sequence by Roman numerals, and each individual is given an Arabic number.

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My Own Grandpa

Simple Recessive HereditySimple Recessive Heredity

• Most genetic disorders are caused by recessive alleles.

Cystic fibrosisCystic fibrosis

• Cystic fibrosis (CF) is the most common fatal genetic disorder in the US among people of European descent.


• Approximately one in 28 white Americans carries the recessive allele, and one in 2500 children born to white Americans inherits the disorder.

• Due to a defective protein in the plasma membrane, cystic fibrosis results in the formation and accumulation of thick mucus in the lungs and digestive tract.

Tay-Sachs diseaseTay-Sachs disease

• Tay-Sachs disease is a recessive disorder of the central nervous system that is common in people of Jewish European descent.

• In this disorder, a recessive allele results in the absence of an enzyme that normally breaks down a lipid produced and stored in tissues of the central nervous system.

Tay-Sachs diseaseTay-Sachs disease

• Because this lipid fails to break down properly, it accumulates in the cells and death occurs within a few years of birth.

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• Phenylketonuria, also called (PKU), is a recessive disorder that results in the failure to metabolize the amino acid phenylalanine.

• Because phenylalanine cannot be broken down, it and its by-products accumulate in the body and result in severe damage to the central nervous system.

PhenylketonuriaPhenylketonuria

• A PKU test is normally performed on all infants a few days after birth.

• Infants affected by PKU are given a diet that is low in phenylalanine until their brains are fully developed.

• Ironically, the success of treating phenylketonuria infants has resulted in a new problem.


• If a female who is homozygous recessive for PKU becomes pregnant, the high phenylalanine levels in her blood can damage her fetus—the developing baby.

• This problem occurs even if the fetus is heterozygous and would be phenotypically normal.



Phenylketonurics: Contains Phenylalanine

Simple Dominant HereditySimple Dominant Heredity

• Remember that in Mendelian inheritance, a single dominant allele inherited from one parent is all that is needed for a person to show the dominant trait.

• Many traits are inherited just as the rule of dominance predicts.

Simple dominant traitsSimple dominant traits

• A cleft chin, widow’s peak hairline, hitchhiker’s thumb, almond shaped eyes, thick lips, and the presence of hair on the middle section of your fingers all are examples of dominant traits.

Huntington’s diseaseHuntington’s disease

• Huntington’s disease is a lethal genetic disorder caused by a rare dominant allele.

• It results in a breakdown of certain areas of the brain and nervous system.

Huntington’s diseaseHuntington’s disease• Ordinarily, a dominant allele with such severe

effects would result in death before the affected individual could have children and pass the allele on to the next generation.

• But because the onset of Huntington’s disease usually occurs between the ages of 30 and 50, an individual may already have had children before knowing whether he or she is affected.

Typical Pedigree of Huntington’s DiseaseTypical Pedigree of Huntington’s Disease

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Fold a vertical sheet of notebook paper from side to side.

To return to the chapter summary click escape or close this document.

Cut along every fifth line of only the top layer to form tabs.


Label each tab with a pedigree symbol.


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Question 1

What does this pedigree tell you about those who show the recessive phenotype for the disease?

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The pedigree indicates that showing the recessive phenotype for the disease is fatal.

Question 2

What must happen for a person to show a recessive phenotype?

Answer

The person must inherit a recessive allele for the trait from both parents.

Question 3

Which of the following diseases is the result of a dominant allele?

D. phenylketonuria

C. cystic fibrosis

B. Tay-Sachs disease

A. Huntington’s disease

The answer is A.

1. What is the dominant flower color in the Mendelian cross?

2. How does the snapdragon cross differ from the Mendelian cross?

Genetics


When Heredity Follows Different Rules

Complex Patterns of InheritanceComplex Patterns of Inheritance

• Patterns of inheritance that are explained by Mendel’s experiments are often referred to as simple.

• However, many inheritance patterns are more complex than those studied by Mendel.

Incomplete dominance: Appearance of a third phenotypeIncomplete dominance: Appearance of a third phenotype

• When inheritance follows a pattern of dominance, heterozygous and homozygous dominant individuals both have the same phenotype.

• Incomplete dominance: the phenotype of heterozygous individuals is intermediate between those of the two homozygotes.

Incomplete dominance: Appearance of a third phenotypeIncomplete dominance: Appearance of a third phenotype

• For example, if a homozygous red-flowered snapdragon plant (RR) is crossed with a homozygous white-flowered snapdragon plant (R′ R′), all of the F1 offspring will have pink flowers.

• A prime symbol is used to show incomplete dominance, a lower case letter is not used.

Incomplete dominance: Appearance of a third phenotype

Incomplete dominance: Appearance of a third phenotype

Red White

All pink

Red (RR)

White (R’R’)

Pink (RR’)

Pink (RR’)

All pink flowers 1 red: 2 pink: 1 white

Codominance: Expression of both allelesCodominance: Expression of both alleles

• Codominant alleles: cause the phenotypes of both homozygotes to be produced in heterozygous individuals; both alleles are expressed equally.

Example of Codominance• Ex: Feather colors in

chickens

• Black (BB) x White (WW) = Black and White checkered Chicken

B B

W

W

BW

BWBW

BW

http://www.omlet.co.uk/images/plyrockbantam_white_m_200.gif

http://www.scotsdumpy.co.uk/scotsdumpyla.jpg

Multiple phenotypes from multiple allelesMultiple phenotypes from multiple alleles

• Although each trait has only two alleles in the patterns of heredity you have studied thus far, it is common for more than two alleles to control a trait in a population.

• Multiple alleles: traits controlled by more than two alleles

Multiple phenotypes from multiple alleles

• In pigeons a single gene controls feather color. There are 3 alleles for feather color.

• BA = ash red feathers• b = chocolate feathers• B = Blue feathers

Multiple phenotypes from multiple alleles

• b is recessive

• B is dominant to b but recessive to BA

• BA is dominant over both B and b.

BABA, BAB, BAb

• In humans the diploid number of chromosomes is 46, or 23 pairs.

• Autosomes: chromosomes that come in homologous chromosomes (22 pairs in humans). Homologous autosomes look alike.

• The 23rd pair of chromosomes differs in males and females.

Sex determinationSex determination

• Sex chromosomes: determine the sex of an individual, are called and are indicated by the letters X and Y.


Sex determinationSex determination• If you are female,

your 23rd pair of chromosomes are homologous, XX.

• If you are male, your 23rd pair of chromosomes XY, look different.

X X

Female

YX

Male

• Males usually have one X and one Y chromosome and produce two kinds of gametes, X and Y.

• Females usually have two X chromosomes and produce only X gametes.

• It is the male gamete that determines the sex of the offspring.



XX Female

XY Male

X

X

X Y

XX Female

XY Male

XX Female

XY Male

• Sex-linked traits: traits controlled by genes located on sex chromosomes

• The alleles for sex-linked traits are written as superscripts of the X or Y chromosomes.

• Because the X and Y chromosomes are not homologous, the Y chromosome has no corresponding allele to one on the X chromosome and no superscript is used.

Sex-linked inheritanceSex-linked inheritance

• Also remember that any recessive allele on the X chromosome of a male will not be masked by a corresponding dominant allele on the Y chromosome.


Females:

Males:1/2 red eyed1/2 white eyed

all red eyed

White-eyed male (XrY)

Red-eyed female (XRXR)

F1 All red eyed

F2


• Polygenic inheritance: the inheritance pattern of a trait that is controlled by two or more genes.

• The genes may be on the same chromosome or on different chromosomes, and each gene may have two or more alleles.

• Uppercase and lowercase letters are used to represent the alleles.

Polygenic inheritancePolygenic inheritance


• However, the allele represented by an uppercase letter is not dominant. All heterozygotes are intermediate in phenotype.

• In polygenic inheritance, each allele represented by an uppercase letter contributes a small, but equal, portion to the trait being expressed.

• The result is that the phenotypes usually show a continuous range of variability from the minimum value of the trait to the maximum value.


• AABBCC is a 16 cm tall plant, aabbcc is a 4 cm tall plant.

• The difference in height is 12 cm or 2 cm/allele.


• If a plant has genotype AaBbCc, how tall would it be?

• The base height is 4 cm and you add 2cm for each dominant allele, so 4 cm + 6 cm = 10 cm tall.

Environmental InfluencesEnvironmental Influences

• The genetic makeup of an organism at fertilization determines only the organism’s potential to develop and function.

• As the organism develops, many factors can influence how the gene is expressed, or even whether the gene is expressed at all.

• Two such influences are the organism’s external and internal environments.

• Temperature, nutrition, light, chemicals, and infectious agents all can influence gene expression.

Influence of external environmentInfluence of external environment


• In arctic foxes temperature has an effect on the expression of coat color.

• External influences can also be seen in leaves. Leaves can have different sizes, thicknesses, and shapes depending on the amount of light they receive.


Influence of internal environmentInfluence of internal environment• The internal

environments of males and females are different because of hormones and structural differences.

• An organism’s age can also affect gene function.

What is the difference between simple Mendelian inheritance and codominant inheritance?

Question 1

In Mendelian inheritance, heterozygous individuals will display the inherited dominant trait of the homozygotes. When traits are inherited in a codominant pattern the phenotypes of both homozygotes are displayed equally in the heterozygotes.

Which of the following does NOT have an effect on male-pattern baldness?

Question 2

D. incomplete dominance

C. sex-linked inheritance

B. internal environment

A. hormones

The answer is D.

If the offspring of human mating have a 50-50 chance of being either male or female, why is the ratio not exactly 1:1 in a small population?

Question 3

Answer

The ratio is not exactly 1:1 because the laws of probability govern fertilization.

1. How many different hair colors are shown?

2. Is this trait inherited as a simple Mendelian trait? How do you know?

Genetics


Complex Inheritance of Human Traits

• Remember that in codominance, the phenotypes of both homozygotes are produced in the heterozygote.

Codominance in Humans

• One example of this in humans is a group of inherited red blood cell disorders called sickle-cell disease.

• Sickle-cell anemia is most common in black Americans whose families originated in Africa and in white Americans whose families originated in countries surrounding the Mediterranean Sea.

Codominance in Humans

• 1/12 African-Americans is heterozygous for the disorder.

• In an individual who is homozygous for the sickle-cell allele, the oxygen-carrying protein hemoglobin differs by one amino acid from normal hemoglobin.

Sickle-cell disease

• This defective hemoglobin forms crystal-like structures that change the shape of the red blood cells. Normal red blood cells are disc-shaped, but abnormal red blood cells are shaped like a sickle, or half-moon.

• The change in shape occurs in the body’s narrow capillaries after the hemoglobin delivers oxygen to the cells.

Sickle-cell disease

Normal red blood cell

Sickle cell

Sickle-cell disease

• Abnormally shaped blood cells, slow blood flow, block small vessels, and result in tissue damage and pain.

Normal red blood cell

Sickle cell

• Individuals who are heterozygous for the allele produce both normal and sickled hemoglobin, an example of codominance.

Sickle-cell disease

• Individuals who are heterozygous are said to have the sickle-cell trait because they can show some signs of sickle-cell-related disorders if the availability of oxygen is reduced.

• Mendel’s laws of heredity also can be applied to traits that have more than two alleles.

Multiple Alleles Govern Blood Type

• The ABO blood group is a classic example of a single gene that has multiple alleles in humans.

Multiple Alleles Govern Blood Type

Human Blood Types

lA lA or lAilB lB or lBilA lB

ii

Genotypes Surface Molecules Phenotypes

AB

A and BNone

ABABO

• Determining blood type is necessary before a person can receive a blood transfusion because the red blood cells of incompatible blood types could clump together, causing death.

The importance of blood typing

100 Greatest Discoveries in Medicine

• The gene for blood type, gene l, codes for a molecule that attaches to a membrane protein found on the surface of red blood cells.

The ABO Blood Group

• The lA and lB alleles each code for a different molecule.

• Your immune system recognizes the red blood cells as belonging to you. If cells with a different surface molecule enter your body, your immune system will attack them.

• The lA allele is dominant to i, so inheriting either the lAi alleles or the lA lA alleles from both parents will give you type A blood.

Phenotype A

• Surface molecule A is produced.

Surface molecule A

• The lB allele is also dominant to i.

Phenotype B

• To have type B blood, you must inherit the lB allele from one parent and either another lB allele or the i allele from the other.

• Surface molecule B is produced.

Surface molecule B

• The lA and lB alleles are codominant.

Phenotype AB

• This means that if you inherit the lA allele from one parent and the lB allele from the other, your red blood cells will produce both surface molecules and you will have type AB blood.

Surface molecule B

Surface molecule A

• The i allele is recessive and produces no surface molecules.

Phenotype O

• Therefore, if you are homozygous ii, your blood cells have no surface molecules and you have blood type O.

• Many human traits are determined by genes that are carried on the sex chromosomes; most of these genes are located on the X chromosome.

Sex-Linked Traits in Humans

• The pattern of sex-linked inheritance is explained by the fact that males, who are XY, pass an X chromosome to each daughter and a Y chromosome to each son.

• Females, who are XX, pass one of their X chromosomes to each child.


Male Female

Sperm Eggs

FemaleFemale MaleMale

Female Male

MaleMaleFemale Female

Eggs Sperm

• If a son receives an X chromosome with a recessive allele, the recessive phenotype will be expressed because he does not inherit on the Y chromosome from his father a dominant allele that would mask the expression of the recessive allele.


• Two traits that are governed by X-linked recessive inheritance in humans are red-green color blindness and hemophilia.

• People who have red-green color blindness can’t differentiate these two colors. Color blindness is caused by the inheritance of a recessive allele on the X chromosome.

Red-green color blindness

• Therefore, it is not possible for a father to pass the color blindness gene to his son.

• He can pass it on to his daughter, though.

Red-green color blindness

• Hemophilia A is an X-linked disorder that causes a problem with blood clotting.

Hemophilia: An X-linked disorder

• About one male in every 10 000 has hemophilia, but only about one in 100 million females inherits the same disorder.

• Males inherit the allele for hemophilia on the X chromosome from their carrier mothers. One recessive allele for hemophilia will cause the disorder in males.

Hemophilia: An X-linked disorder

• Females would need two recessive alleles to inherit hemophilia.

• Although many of your traits were inherited through simple Mendelian patterns or through multiple alleles, many other human traits are determined by polygenic inheritance.

Polygenic Inheritance in Humans

• In the early 1900s, the idea that polygenic inheritance occurs in humans was first tested using data collected on skin color.

• Scientists found that when light-skinned people mate with dark-skinned people, their offspring have intermediate skin colors.

Skin color: A polygenic trait

• This graph shows the expected distribution of human skin color if controlled by one, three, or four genes.

Skin color: A polygenic trait

Number of Genes Involved in Skin Color

Observed distribution of skin color

Expected distribution- 1 gene

Expected distribution- 4 genes

Expected distribution- 3 genes

Range of skin colorLight Right

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als

• What would happen if an entire chromosome or part of a chromosome were missing from the complete set?

Changes in Chromosome Numbers

• As you have learned, abnormal numbers of chromosomes in offspring usually, but not always, result from accidents of meiosis.

• Many abnormal phenotypic effects result from such mistakes.

• Humans who have an extra whole or partial autosome are trisomic—that is, they have three of a particular autosomal chromosome instead of just two. In other words, they have 47 chromosomes.

Abnormal numbers of autosomes

• To identify an abnormal number of chromosomes, a sample of cells is obtained from an individual or from a fetus.

• Metaphase chromosomes are photographed; the chromosome pictures are then enlarged and arranged in pairs by a computer according to length and location of the centromere.


• Karyotype: chart of chromosome pairs; valuable in identifying unusual chromosome numbers in cells


• Down syndrome is the only autosomal trisomy in which affected individuals survive to adulthood.

Down syndrome: Trisomy 21

• It occurs in about one in 700 live births.

• Down syndrome is a group of symptoms that results from trisomy of chromosome 21.

Down syndrome: Trisomy 21

• Individuals who have Down syndrome have at least some degree of mental retardation.

• The incidence of Down syndrome births is higher in older mothers, especially those over 40.

• Many abnormalities in the number of sex chromosomes are known to exist.

Abnormal numbers of sex chromosomes

• Turner Syndrome: an X chromosome may be missing (45, XO), female

• Klinefelter Syndrome: an extra X chromosome (47, XXY), male

• Jacob Syndrome: an extra Y chromosome (47, XYY)

• Any individual with at least one Y chromosome is a male, and any individual without a Y chromosome is a female.

Abnormal numbers of sex chromosomes

• Most of these individuals lead normal lives, but they cannot have children and some have varying degrees of mental retardation.

Which of the following inherited diseases would a black American be most likely to inherit?

Question 1

D. sickle-cell disease

C. phenylketonuria

B. Tay-Sachs disease

A. cystic fibrosis

The answer is D.

Trisomy usually results from _______.

Question 2

D. twenty-two pairs of chromosomes

C. nondisjunction

B. incomplete dominance

A. polygenic inheritance

The answer is C.

How do red blood cells of phenotype O differ from the cells of the other phenotypes?

Question 3

Answer

Red blood cells of phenotype O display no surface molecules.

Question 1

Which of the following is NOT a sex-linked trait?

D. red-green color blindness

C. male patterned baldness

B. sickle-cell disease

A. hemophilia

The answer is B.

Question 2

Human eye color is determined by _______.

D. polygenic inheritance

C. codominance

B. sex-linked inheritance

A. the influence of hormones

The answer is D.

Question 3

What are blood phenotypes based on?

Answer

Blood phenotypes are based on a molecule that attaches to a membrane protein found on the surface of red blood cells.

Question 4

Cob length in corn is the result of _______.

D. simple dominance

C. polygenic inheritance


A. sex-linked inheritance

The answer is C.

Question 5

A cleft chin is the result of _______.

D. sex-linked inheritance

C. polygenic inheritance


A. simple dominance

The answer is A.

Question 6

What is the difference between simple Mendelian inheritance and inheritance by incomplete dominance?

In Mendelian inheritance, heterozygous individuals will display the inherited dominant trait of the homozygotes. However, when traits are inherited in an incomplete dominance pattern, the phenotype of heterozygous individuals is intermediate between those of the two homozygotes.

Question 7

If a trait is Y-linked, males pass the Y-linked allele to _______ of their daughters.

D. none

C. all

B. half

A. a quarter

The answer is D. Y-linked traits are only passed to males.

Question 8

What is necessary for a person to show a dominant trait?

Answer

The person must inherit at least a single dominant allele from one parent for the trait to appear.

Question 9

Why is sickle-cell disease considered to be an example of codominant inheritance?

Answer

Individuals who are heterozygous for the sickle-cell allele produce both normal and sickled hemoglobin. This is an example of codominance.

Question 10

What sex is an XXY individual?

Answer

Any individual with at least one Y chromosome is a male.

• How could this circuit diagram help an engineer find and repair a problem with a circuit?

• How might having a “diagram” of the location of all human genes be helpful?

Genetics

The Human Genome

Genetic Technology

• In 1990, scientists in the United States organized the Human Genome Project (HGP). It is an international effort to completely map and sequence the human genome.

• Human genome: the approximately 35,000- 40,000 genes on the 46 human chromosomes

Mapping and Sequencing the Human Genome

• In February of 2001, the HGP published its working draft of the 3 billion base pairs of DNA in most human cells.

Mapping and Sequencing the Human Genome

• The sequence of chromosomes 21 and 22 was finished by May 2000.

• Linkage map: a genetic map that shows the relative locations of genes on a chromosome

Linkage maps

• The historical method used to assign genes to a particular human chromosome was to study linkage data from human pedigrees.

• Because humans have only a few offspring compared with the larger numbers of offspring in some other species, and because a human generation time is so long, mapping by linkage data is extremely inefficient.

Linkage maps

• Biotechnology now has provided scientists with new methods of mapping genes.

• A genetic marker is a segment of DNA with an identifiable physical location on a chromosome and whose inheritance can be followed.

Linkage maps

• A marker can be a gene, or it can be some section of DNA with no known function.

• Because DNA segments that are near each other on a chromosome tend to be inherited together, markers are often used as indirect ways of tracking the inheritance pattern of a gene that has not yet been identified, but whose approximate location is known.

Linkage maps

• The difficult job of sequencing the human genome is begun by cleaving samples of DNA into fragments using restriction enzymes.

Sequencing the human genome

• Then, each individual fragment is cloned and sequenced. The cloned fragments are aligned in the proper order by overlapping matching sequences, thus determining the sequence of a longer fragment.

• Improved techniques for prenatal diagnosis of human disorders, use of gene therapy, and development of new methods of crime detection are areas currently being researched.

Applications of the Human Genome Project

• One of the most important benefits of the HGP has been the diagnosis of genetic disorders.

Diagnosis of genetic disorders

Diagnosis of genetic disorders

• The DNA of people with and without a genetic disorder is compared to find differences that are associated with the disorder. Once it is clearly understood where a gene is located and that a mutation in the gene causes the disorder, a diagnosis can be made for an individual, even before birth.

• Individuals who inherit a serious genetic disorder may now have hope—gene therapy.

• Gene therapy: the insertion of normal genes into human cells to correct genetic disorders.

Gene therapy

• Trials that treat SCID (severe combined immunodeficiency syndrome) have been the most successful.

• In this disorder, a person’s immune system is shut down and even slight colds can be life-threatening.

Gene therapy

• In gene therapy for this disorder, the cells of the immune system are removed from the patient’s bone marrow, and the functional gene is added to them.

• The modified cells are then injected back into the patient.

Gene therapy

Gene therapy

Cell culture flask

Bone marrow cells

Bone marrow cell with integrated gene

Add virus with functioning SCID gene

Gene

Hip Bone

• Other trials involve gene therapy for cystic fibrosis, sickle-cell anemia, hemophilia, and other genetic disorders

• It is hoped that in the next decade DNA technology that uses gene therapy will be developed to treat many different disorders.

Gene therapy

A segment of DNA with an identifiable physical location on a chromosome and whose inheritance can be followed is a _______.

Question 1

D. linkage map C. nitrogenous base B. genetic marker A. genome

The answer is B.

Why is mapping by linkage data inefficient in humans?

Question 2

Answer

Mapping by linkage data is inefficient in humans because humans have only a few offspring and because a human generation is so long.

The insertion of normal genes into human cells to correct genetic disorders is called _______.

Question 3

D. gene therapy

C. genome sequencing B. genetic engineering

A. DNA fingerprinting

The answer is D.

Question 1

DNA fingerprinting is based on distinct combinations of patterns in DNA produced by _______.

D. stop codons

C. anticodons

B. exons

A. Noncoding DNA

The answer is A.

Question 2

The human genome contains approximately ________ genes.

D. 23,000 C. 35,000

B. 3,500 A. 46

The answer is C.

What is a live vector vaccine?

Question 7

Answer

An antigen-coding gene from a disease-causing virus is inserted into a harmless carrier virus. When a vaccine made from the carrier virus is injected into a host, the virus replicates and in the process produces the antigen protein, causing an immune response.

How is severe combined immunodeficiency syndrome (SCID) being treated with gene therapy?

Question 8

Answer

Cells of the immune system are removed from the patient’s bone marrow, and the functional gene is added to them.

How does a DNA vaccine work?

Question 9

Answer

DNA vaccines differ from other vaccines in that only the cloned segment of DNA that codes for a disease-causing antigen is injected into a host. The DNA is the vaccine.

12.1 section objectives – page 309 1. which of these traits do you have? 2. how would knowing your...

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