How Tall is Tall?
                                 Choose a partner. Use a
                                 meter stick to...
Blood type is controlled by a       Traits Controlled by Many
gene with multiple alleles                   Genes
         ...
The sex chromosomes
determine whether a person is
male or female.
The sex chromosomes are the
only pair of chromosomes tha...
Sex-Linked Genes
      Sex-
Some human traits occur more
often in one gender than the       In females, a dominant allele
...
Discover Activity              Genetic Disorders

Turn to pg. 125                 Genetic Disorder: An abnormal
Work with ...
Diagnosing Genetic Disorders        Karyotype: A picture of all of
                                    Karyotype:
        ...
Genetic Engineering

Remember: Just because you      Genetic Engineering: Genes
could, doesn’t mean that you
could, doesn’...
Upcoming SlideShare
Loading in …5
×

Chapter 4 Chapter 4

704
-1

Published on

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
704
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
5
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Chapter 4 Chapter 4

  1. 1. How Tall is Tall? Choose a partner. Use a meter stick to measure each other’s height to the nearest other’ Chapter 4 inch. Write your measurements on a Modern Genetics piece of paper. As a class, create a bar graph of the class heights on the board. Traits Controlled by Single Genes Many human traits are Each allele controls a different controlled by a single gene form of the trait These genes have two different alleles – dominant and recessive Multiple Alleles Some human traits are Even though a gene may have controlled by a single gene multiple alleles, a person can that has more than two alleles only carry two of those alleles Multiples Alleles: Three or Chromosomes exist in pairs – more forms of a gene that Each chromosome in a pair code for a single trait only carries one allele for each gene 1
  2. 2. Blood type is controlled by a Traits Controlled by Many gene with multiple alleles Genes Some human traits show a large number of phenotypes because the traits are controlled by many genes. The genes act together as a group to produce a single trait. Remember the height activity and the range of phenotypes we saw. The Environment The effects if genes are Height is controlled by four genes working together. altered by our environment. Skin color is controlled by at EX: Diet can affect height – a least three genes, each one diet that lacks proper nutrition containing two different alleles. can prevent a person from Various combinations of reaching their potential height alleles produce the many skin colors in humans Male or Female? The gender of a baby is Other factors include living determined by genes on conditions and modern health chromosomes. care There are 23 pairs of chromosomes in each of our cells. One of pair of chromosomes are called sex chromosomes. 2
  3. 3. The sex chromosomes determine whether a person is male or female. The sex chromosomes are the only pair of chromosomes that do not always match. Draw this in your notes Females The two sex chromosomes match - XX Males The two sex chromosomes do not match - XY Since both of a female’s sex female’ Figure 4 on pg. 121 – copy this chromosomes are X, all eggs into your notes carry one X chromosome Complete the “Try This” This” Males have two different sex activity on pg. 122. Answer chromosomes, so sperm cells the questions in your notes will either carry an X or a Y chromosome 3
  4. 4. Sex-Linked Genes Sex- Some human traits occur more often in one gender than the In females, a dominant allele other. on one X chromosome will mask a recessive allele on the Sex-Linked Genes: Genes on Sex- other X chromosome. the X and Y chromosomes, whose alleles are passed from parent to offspring on sex chromosomes In males, there is no matching Because males have only one allele on the X and Y X chromosome, males are chromosome. As a result, any more likely than females to allele on the X chromosome have a sex-linked trait that is sex- will produce the trait in a male controlled by a recessive who inherits it. allele. Example of sex-linked trait sex- Pedigrees controlled by a recessive allele: red-green color red- Pedigree: A chart or “family blindness tree” that tracks which tree” Affects more members of a family have a males than particular trait females 4
  5. 5. Discover Activity Genetic Disorders Turn to pg. 125 Genetic Disorder: An abnormal Work with your neighbor to do condition that a person inherits the activity in your notes through genes or chromosomes Genetic disorders are caused by mutations Cystic Fibrosis Sickle-Cell Disease Sickle- Genetic disorder that affects Genetic disorder in which the the production of hemoglobin body produces too much in the blood. mucus in the lungs and This causes blocked blood intestines. vessels, which leads to The mucus makes it hard to difficulty breathing, breathe and digest food pain and weakness Hemophilia Down Syndrome Genetic disorder in which a Genetic disorder resulting from person’s blood clots very person’ having an extra copy of slowly or not at all. chromosome 21. A person with hemophilia can bleed to death from a minor cut. 5
  6. 6. Diagnosing Genetic Disorders Karyotype: A picture of all of Karyotype: the chromosomes in the cell. Doctors use amniocentesis and karyotypes to detect The chromosomes are genetic disorders. arranged in pairs. Amniocentesis: A doctor uses a long needle to remove a small amount of fluid that surrounds a baby while it is in the womb Advances in Genetics Selective Breeding Selective Breeding: Breeding Three methods that people organisms with desired traits have used to develop so that their offspring will have organisms with desirable traits: those traits Selective breeding Cloning Genetic Engineering Cloning Inbreeding: Crossing two Clone: An organism that is individuals with similar or genetically identical to the identical alleles – increases organism from which it was genetic disorders (EX: produced Smokey) Cloning can be done with Hybridization: Breeding two plants and animals genetically different individuals 6
  7. 7. Genetic Engineering Remember: Just because you Genetic Engineering: Genes could, doesn’t mean that you could, doesn’ from one organism are should! should! transferred into the DNA of another organism Used to produce medicine, improve crops, and cure genetic disorders The Human Genome Project The main goal of the human genome project is to identify every gene in human DNA. How can this help improve modern medicine? 7

×