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6.1 Human Inheritance

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Title: 6.1 Human Inheritance


1
Table of Contents
  • 6.1 Human Inheritance
  • 6.2 Human Genetic Disorders
  • 6.3 Advances in Genetics

Chapter Preview 1.1 Thinking Like a
Scientist 1.2 The Study of Life 1.3 Scientific
Inquiry 1.4 Safety in the Laboratory
Chapter Preview 6.1 Human Inheritance 6.2 Human
Genetic Disorders 6.3 Advances in Genetics
2
Chapter Preview Questions
  • 1. From each parent, offspring inherit
  • a. half their phenotypes.
  • b. half their traits.
  • c. half their genes.
  • d. half their chromosomes.

3
Chapter Preview Questions
  • 1. From each parent, offspring inherit
  • a. half their phenotypes.
  • b. half their traits.
  • c. half their genes.
  • d. half their chromosomes.

4
Chapter Preview Questions
  • 2. Plant and animal cells typically have
  • a. three copies of every gene.
  • b. two copies of every gene.
  • c. varying copies of every gene.
  • d. one copy of every gene.

5
Chapter Preview Questions
  • 2. Plant and animal cells typically have
  • a. three copies of every gene.
  • b. two copies of every gene.
  • c. varying copies of every gene.
  • d. one copy of every gene.

6
Chapter Preview Questions
  • 3. The genetic material of living organisms is
  • a. cytoplasm.
  • b. mitochondria.
  • c. chromosomes.
  • d. DNA.

7
Chapter Preview Questions
  • 3. The genetic material of living organisms is
  • a. cytoplasm.
  • b. mitochondria.
  • c. chromosomes.
  • d. DNA.

8
Chapter Preview Questions
  • 4. The chromosomes of each cell in an organism
    are where
  • a. DNA is located.
  • b. sexual reproduction occurs.
  • c. gender identity is determined.
  • d. photosynthesis takes place.

9
Chapter Preview Questions
  • 4. The chromosomes of each cell in an organism
    are where
  • a. DNA is located.
  • b. sexual reproduction occurs.
  • c. gender identity is determined.
  • d. photosynthesis takes place.

10
How are traits inherited in people?
  • Suppose you have a friend who
  • doesnt have freckles. Both of her
  • biological parents have freckles.
  • The allele for freckles is dominant.
  • What can you infer about the
  • genotype of your friends parents?
  • Explain your answer.

11
High-Use Academic Words
Word Definition Example Sentence

adj. Usual, typical, expected
Its normal to feel nervous about going to a new
school.
normal
12
High-Use Academic Words
Word Definition Example Sentence

n. The way in which parts of something are
connected
You have learned the basic structure of plant and
animal cells.
structure
13
High-Use Academic Words
Word Definition Example Sentence

v. To influence to produce a change in
Scientists are looking for ways to treat diseases
that affect people.
affect
14
High-Use Academic Words
Word Definition Example Sentence

n. A special way of doing something, a method, a
procedure
There are special techniques for balancing on a
skateboard.
technique
15
  • Apply It!
  • Choose the word that best completes each
    sentence.
  • 1. Peoples diets can their health.
  • affect
  • 2. Doctors have developed a new
    for doing heart surgery.
  • technique
  • 3. A(n) body temperature in a
    human is about 37C.
  • normal

16
End of Chapter Preview
17
Section 1 Human Inheritance
  • What are some patterns of inheritance in humans?
  • What are the functions of the sex chromosomes?
  • What is the relationship between genes and the
    environment?

18
Patterns of Human Inheritance
  • A single gene can have more than two alleles
  • There is not always a one-to-one correspondence
    between trait and gene
  • Key concept Some human traits are controlled by
    single genes with two alleles, and other by
    single genes with multiple alleles. Still other
    traits are controlled by many genes that act
    together.
  • What we discussed in chapter 5 single gene with
    2 alleles

19
Single Genes with Multiple Alleles
  • Multiple alleles- 3 or more forms of a gene that
    code for a single trait.
  • People carry only 2 alleles for each trait
  • Each chromosome carries one allele for each gene

Blood type is determined by a single gene with
three alleles. This chart shows which
combinations of alleles result in each blood type.
20
Traits Controlled by Many Genes
  • Some traits show a large number of phenotypes
    because the traits are controlled by multiple
    alleles (ex. Height)
  • Skin, eyes, hair color are also controlled by
    multiple alleles

21
The Sex Chromosomes
  • The sex chromosomes carry genes that determine
    whether a person is male or female. They also
    carry genes that determine other traits.

22
The Sex Chromosomes
  • Key concept The sex chromosomes carry genes
    that determine whether a person is male or
    female. They also carry genes that determine
    other traits.
  • Sex chromosomes are one of the 23 pairs of
    chromosomes in a human body
  • Only chromosomes that sometimes dont match

Females have XX Males have XY
23
Sex Linked Genes
  • Sex-linked Genes- genes on the X or Y
    chromosomes, these are passed from parent to
    offspring on the sex chromosome
  • Many of the genes on the X chromosomes are not on
    the Y chromosomes
  • Because males have only one X they are more
    likely to have a sex-linked gene than females

24
Colorblindness Punnett Square
  • Red-green colorblindness is a sex-linked trait. A
    girl who receives only one recessive allele
    (written Xc) for red-green colorblindness will
    not have the trait. However, a boy who receives
    one recessive allele will be colorblind. Carrier-
    person who has one recessive allele for a trait
    and one dominant

25
Colorblindness
What sex is the person that is a carrier for
colorblindness?
26
The Effect of Environment
  • Key concept Many of an organisms
    characteristics are determined by an interaction
    between genes and the environment.
  • A diet lacking in protein, minerals, vitamins,
    can affect growth

27
End of Section Human Inheritance
28
Section 2 Human Genetic Disorders
  • What are two major causes of genetic disorders in
    humans?
  • How do geneticists trace the inheritance of
    traits?
  • How are genetic disorder diagnosed and treated?

29
Cause of Genetic Disorders
  • Genetic disorder- an abnormal condition that a
    person inherits through genes or chromosomes
  • Key concept Some genetic disorders are caused
    by changes in the DNA of genes. Other disorders
    are caused by changes in the overall structure or
    number of chromosomes.

30
A Pedigree
  • A pedigree is a chart or family tree that
    tracks which members of a family have a
    particular trait.

31
Genetic Disorders
  • Cystic Fibrosis
  • Sickle-cell disease
  • caused by a recessive allele as a result of a
    mutation
  • body produces abnormally thick mucus in the lungs
    and intestines
  • makes it hard to breathe
  • codominant with normal cells
  • person with two sickle-cell alleles has the
    disease
  • person with one sickle-cell allele has both
    normal and abnormal hemoglobin
  • unusual shaped blood cells that clogs the blood
    vessels

32
Genetic Disorders
  • Hemophilia
  • Down Syndrome
  • Caused by a recessive allele on the X chromosome
  • Sex-linked
  • Blood cots very slowly or not at all
  • Person doesnt produce one of the proteins needed
    for clotting
  • Extra copy of chromosome 21
  • Most often happens when a chromosome fails to
    separate during meiosis

33
A Hemophilia Pedigree
  • Pedigree- a chart that tracks members of a family
    with a particular trait
  • Key Concept One important tool that geneticists
    use to trace the inheritance of traits in humans
    is a pedigree.
  • Pedigrees can be about normal traits like widows
    peak or genetic disorders
  • This pedigree shows the inheritance of hemophilia
    in a family.

34
A Hemophilia Pedigree
  • The pedigree shows the inheritance of hemophilia,
    a sex-linked disorder in a family.

35
Managing Genetic Disorders
  • Key Concept Today, doctors use tools such as
    karyotypes to help diagnose genetic disorders.
    People with genetic disorders are helped through
    medical care, education, job training, and other
    methods.
  • Doctors use Punnett squares and pedigrees to
    help predict whether a child might have a genetic
    disorder or not
  • Karyotype- a picture of all the chromosomes in a
    cell showing if a person has the correct number
    of chromosomes or not

36
Managing Genetic Disorders
Karyotyping
  • Genetic counseling
  • Families that have a history of a genetic
    disorder
  • Help people understand the chances of having a
    child with a specific disorder
  • Use Punnett squares, pedigrees, karyotypes to help

Punnett square
Pedigree
37
Managing Genetic Disorders
  • Dealing with Genetic Disorders
  • Deal with serious challenges
  • Modify environment
  • Medicine, diet, and vitamins
  • Education
  • People can still live active and productive lives

38
End of Section Human Genetic Disorders
39
Section 3 Advances in Genetics
  • What are three ways of producing organisms with
    desired traits?
  • What are two applications of DNA technology in
    human genetics?

40
Selective Breeding
  • Key concept Selective breeding, cloning, and
    genetic engineering are three methods for
    developing organisms with desirable trait.
  • Selective breeding- the process of breeding
    organisms with desired traits
  • Inbreeding- crossing two individuals that have
    similar characteristics
  • Inbreeding increases the probability of having
    genetic disorders
  • Hybridization- breeders cross two genetically
    different individuals trying to get the best of
    both organisms

41
Cloning
  • Clone- an organism that has the exact same genes
    as the organism from which it was produced
  • You can clone some plants easily because all you
    do is cut a piece off and plant it- new plant is
    genetically identical to the original plant
  • Animals are more difficult to clone, they take
    the nucleus out of a body cell and use it to
    produce a new animal

42
Genetic Engineering
  • Genetic engineering- genes from one organism are
    put into the DNA of another
  • Genetic engineering can produce and improve
    medicines and foods.
  • Genes have been inserted into animals (example-
    creating blood clotting protein to help people
    with hemophilia
  • Genes have been inserted into plants (example-
    creating crops that are resistant to pesticides
  • Gene therapy- inserting copies of a gene into a
    humans cells
  • Concerns about the long-term effects of genetic
    engineering (crops harm environment or health
    problems in people )

43
Genetic Engineering
  • Scientists use genetic engineering to create
    bacterial cells that produce important human
    proteins such as insulin.

44
Learning About Human Genetics
  • Key concept Applications of DNA technology
    include studying the human genome in detail and
    identifying people.
  • Genome- all the DNA in one cell of an organism
  • DNA finger printing is used to show if people are
    related using
  • Except for identical twins every person has
    different DNA fingerprints
  • Scientists use mitochondrial DNA, because it is
    almost identical to the mother, to determine the
    persons identity

45
Human genome project
  • Project goals were to
  • identify all the approximately 30,000-35,000
    genes in human DNA
  • determine the sequences of the 3 billion chemical
    base pairs that make up human DNA
  • store this information in databases
  • improve tools for data analysis

Scientists now know the DNA sequence of almost
every human gene
46
End of Section Advances in Genetics
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