Unit 6 - Genetics Unit 6 - Genetics Introduction Introduction You look the way you do because of the genes your parents passed on to you at fertilization (the joining of the sperm and the egg). The transfer of genes from parents to offspring gives you your unique strand of DNA which every cell in your body uses to function. The scientific study of heredity is called genetics . http:// www.exploringautism.org/ genetics/images/ overview.jpg
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Unit 6 - Genetics Introduction You look the way you do because of the genes your parents passed on to you at fertilization (the joining of the sperm.
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Unit 6 - Genetics Unit 6 - Genetics IntroductionIntroduction
Unit 6 - Genetics Unit 6 - Genetics IntroductionIntroduction
You look the way you do because of the genes your parents passed on to you at fertilization (the joining of the sperm and the egg). The transfer of genes from parents to offspring gives you your unique strand of DNA which every cell in your body uses to function. The scientific study of heredity is called genetics.
You look the way you do because of the genes your parents passed on to you at fertilization (the joining of the sperm and the egg). The transfer of genes from parents to offspring gives you your unique strand of DNA which every cell in your body uses to function. The scientific study of heredity is called genetics.
Types of MutationsTypes of MutationsTypes of MutationsTypes of Mutations
Frameshift Mutations = causes the codons read in the DNA sequence to be completely altered; (create a protein unable to perform normal functions).
Frameshift Mutations = causes the codons read in the DNA sequence to be completely altered; (create a protein unable to perform normal functions).
Point Mutations = changes to one or a few bases at a single point in the DNA sequences (usually one base is changed to another (inversion), one is insertion, or one is deletion).
Point Mutations = changes to one or a few bases at a single point in the DNA sequences (usually one base is changed to another (inversion), one is insertion, or one is deletion).
A mutagen is anything that can cause a mutation in DNA. EX - UV radiation from the sun, chemicals found in asbestos
(used in construction) and cigarette smoke.
A mutagen is anything that can cause a mutation in DNA. EX - UV radiation from the sun, chemicals found in asbestos
(used in construction) and cigarette smoke.
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Genetic DisordersGenetic DisordersGenetic DisordersGenetic Disorders Mutations can be
natural. Sometimes,
mutations in the genetic code are passed.
Diseases found in humans are related to the DNA, called genetic disorders.
Cystic fibrosis, sickle cell anemia, and hemophilia are just some examples of genetic disorders.
Mutations can be natural.
Sometimes, mutations in the genetic code are passed.
Diseases found in humans are related to the DNA, called genetic disorders.
Cystic fibrosis, sickle cell anemia, and hemophilia are just some examples of genetic disorders.
The problems the people have are related to mistakes in their genetic code. Common genetic disorders are listed on pg. 345 – 348 and discussed in Ch. 14.
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The problems the people have are related to mistakes in their genetic code. Common genetic disorders are listed on pg. 345 – 348 and discussed in Ch. 14.
An organism with a mixed allele pair is heterozygous, (Rr) has the opportunity of having offspring with both traits.
If two heterozygous organisms cross, you can have offspring that exhibit (or show) the recessive trait.
An organism with a mixed allele pair is heterozygous, (Rr) has the opportunity of having offspring with both traits.
If two heterozygous organisms cross, you can have offspring that exhibit (or show) the recessive trait. http://discover.edventures.com/images/termlib/h/
The Punnett SquareThe Punnett SquareThe Punnett SquareThe Punnett Square Scientists have now
developed a system using symbol combinations to study heredity.
A Punnett square is a chart used to predict and compare the genetic combinations that will result from a cross.
Scientists have now developed a system using symbol combinations to study heredity.
A Punnett square is a chart used to predict and compare the genetic combinations that will result from a cross. A capital letter represents the dominant trait while a lowercase letter is the recessive trait.
A plant that IS always tall would be TT while a plant that is short would be tt.
A capital letter represents the dominant trait while a lowercase letter is the recessive trait.
A plant that IS always tall would be TT while a plant that is short would be tt.
Co dominanceCo dominanceCo dominanceCo dominance We now know that there are also instances of co
dominance, where there is none that is dominant or recessive but a mixture of both alleles.
An example of co dominance would be roses. A white crossed with a red to produce a pink.
http://www.gwu.edu/~darwin/BiSc150/One/rose.GIF
Multiple AllelesMultiple AllelesMultiple AllelesMultiple Alleles Not all genes have
just two alleles for the trait, but some can have many alleles to choose from and are said to have multiple alleles.
Hair color, eye color, and blood types are all examples of human traits where multiple alleles are involved, not just the standard two often used in punnett squares.
Not all genes have just two alleles for the trait, but some can have many alleles to choose from and are said to have multiple alleles.
Hair color, eye color, and blood types are all examples of human traits where multiple alleles are involved, not just the standard two often used in punnett squares.
Not every trait is controlled by a single gene. Traits that are controlled by two or more genes are said to be polygenic traits, which means “having many genes”.
Human stature (or height) is controlled by multiple genes.
Not every trait is controlled by a single gene. Traits that are controlled by two or more genes are said to be polygenic traits, which means “having many genes”.
Human stature (or height) is controlled by multiple genes.
Mendel began studying genetics in the 1820s, but science has advanced and we know that DNA carries genes in our chromosomes.
In 1911, the first gene map was produced that showed the gene locations on the chromosomes of a fruit fly.
Mendel began studying genetics in the 1820s, but science has advanced and we know that DNA carries genes in our chromosomes.
In 1911, the first gene map was produced that showed the gene locations on the chromosomes of a fruit fly.
The shaded areas represent a gene that controls a specific trait(s).
Gene maps are now widely used in understanding genetic mutations, sickness, and the human genome project.
The shaded areas represent a gene that controls a specific trait(s).
Gene maps are now widely used in understanding genetic mutations, sickness, and the human genome project.
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Fruit FliesFruit FliesFruit FliesFruit Flies
Fruit flies (as shown here) are used to study genes and genetic relationships because they have a small number of chromosomes and can reproduce quickly.
Fruit flies (as shown here) are used to study genes and genetic relationships because they have a small number of chromosomes and can reproduce quickly.
Sperm and egg cells, known as sex cells (gametes), contain all the genetic material needed to build an organism • EX a cat, the zebra at the zoo, or even a little
brother or sister! A sperm is the male sex cell while an egg is the
female sex cell. Sex cells are haploid and have half the number of
chromosomes in a normal cell (diploid). Half of the genes in an organism are from the
mother, the other half from the father.
Sperm and egg cells, known as sex cells (gametes), contain all the genetic material needed to build an organism • EX a cat, the zebra at the zoo, or even a little
brother or sister! A sperm is the male sex cell while an egg is the
female sex cell. Sex cells are haploid and have half the number of
chromosomes in a normal cell (diploid). Half of the genes in an organism are from the
chromosomes total in the body; 44 of them are called autosomes.
Two of the 46 chromosomes in humans are known as sex chromosomes because they determine an individual's sex.
Humans have 46 chromosomes total in the body; 44 of them are called autosomes.
Two of the 46 chromosomes in humans are known as sex chromosomes because they determine an individual's sex. Females most often have two copies of a large X chromosomes (XX)
Males most often have one X and one small Y chromosome (XY).
Females most often have two copies of a large X chromosomes (XX)
Males most often have one X and one small Y chromosome (XY).
Two Factor Punnett Square:Two Factor Punnett Square:Dihybrid CrossDihybrid Cross
Two Factor Punnett Square:Two Factor Punnett Square:Dihybrid CrossDihybrid Cross
We now understand how a simple Punnett square works by outlining the possibilities for one specific trait (eye color = E’s, skin color = G’s.)
The two factor cross shows the possibilities comparing TWO unique traits (using two different letters).
Male = Gg & Ee Female = GG & ee
We now understand how a simple Punnett square works by outlining the possibilities for one specific trait (eye color = E’s, skin color = G’s.)
The two factor cross shows the possibilities comparing TWO unique traits (using two different letters).
Male = Gg & Ee Female = GG & ee
Two Factor Punnett Square:Two Factor Punnett Square:Dihybrid CrossDihybrid Cross
Two Factor Punnett Square:Two Factor Punnett Square:Dihybrid CrossDihybrid Cross
The sex cells for an organism (the sperm and the egg) are known as gametes; these gametes contain the chromosomes which contain the genes.
The first step in a dihybrid (two factor) cross is to determine the gametes.
EX Gg (skin color) & Ee (eyes) in Martians. What genes will be held in the gametes?
Step #1 – Creating the Gametes
1. Draw a box with 4 boxes. 2. Place the skin color genotype (Gg) on the
top of the box. 3. Place the eye genotype (Ee) on the side of
the box. 4. Fill in the four squares. These will be the sex
cells given to the children (gametes).
The sex cells for an organism (the sperm and the egg) are known as gametes; these gametes contain the chromosomes which contain the genes.
The first step in a dihybrid (two factor) cross is to determine the gametes.
EX Gg (skin color) & Ee (eyes) in Martians. What genes will be held in the gametes?
Step #1 – Creating the Gametes
1. Draw a box with 4 boxes. 2. Place the skin color genotype (Gg) on the
top of the box. 3. Place the eye genotype (Ee) on the side of
the box. 4. Fill in the four squares. These will be the sex
cells given to the children (gametes).
Two Factor Punnett Square:Two Factor Punnett Square:Dihybrid CrossDihybrid Cross
Two Factor Punnett Square:Two Factor Punnett Square:Dihybrid CrossDihybrid Cross
Each of these boxes represents a single sperm cell containing these specific genes. Repeat for the eggs.
Each of these boxes represents a single sperm cell containing these specific genes. Repeat for the eggs.
G g
E e
GE gE
Ge ge
Two Factor Punnett Square:Two Factor Punnett Square:Dihybrid CrossDihybrid Cross
Two Factor Punnett Square:Two Factor Punnett Square:Dihybrid CrossDihybrid Cross
Each of these boxes represents a single egg cell containing these specific genes. Repeat for the eggs.
Each of these boxes represents a single egg cell containing these specific genes. Repeat for the eggs.
G G
e e
Ge Ge
Ge Ge
Just as in a single trait Punnett square, the male gametes go on the top of the box and the female gametes on the side of the box.
Step #2 – Filling in the Punnett Square
1. Draw a Punnett square with 16 boxes.
2. Place the gametes on the top and sides (red & blue)
3. Always group the same genes together (G’s with g’s, etc).
EX – in the first box, place a GGEe.
4. Fill in the remaining boxes.
Just as in a single trait Punnett square, the male gametes go on the top of the box and the female gametes on the side of the box.
Step #2 – Filling in the Punnett Square
1. Draw a Punnett square with 16 boxes.
2. Place the gametes on the top and sides (red & blue)
3. Always group the same genes together (G’s with g’s, etc).
EX – in the first box, place a GGEe.
4. Fill in the remaining boxes.
Two Factor Punnett Square:Two Factor Punnett Square:Dihybrid CrossDihybrid Cross
Two Factor Punnett Square:Two Factor Punnett Square:Dihybrid CrossDihybrid Cross
Fill in the Punnett SquareFill in the Punnett SquareDihybrid CrossDihybrid CrossFill in the Punnett SquareFill in the Punnett SquareDihybrid CrossDihybrid Cross
Each of these boxes represents the joining of a sperm and egg to make offspring.
Each of these boxes represents the joining of a sperm and egg to make offspring.
Ge Ge Ge Ge sperm
GE
gE
Ge
geeggs
GGEe GGEe GGEe GGEe
GgEe
GGee
Ggee
Ge Ge Ge Ge sperm
GE
gE
Ge
geeggs
GGEe GGEe GGEe GGEe
GgEe
GGee
Ggee
A dihybrid Punnett square shows 16 possible genotypic combinations.
A dihybrid Punnett square shows 16 possible genotypic combinations.
Conclusion: Conclusion: Genetics and the Future Genetics and the Future
Conclusion: Conclusion: Genetics and the Future Genetics and the Future Genetics and DNA
technology improves daily in the scientific community.
The entire human DNA strand is mapped, many genes are identified; scientist are currently discovering which genes control which functions.
In your journal, predict what you think our knowledge of our DNA and genetics will have on the future?
Genetics and DNA technology improves daily in the scientific community.
The entire human DNA strand is mapped, many genes are identified; scientist are currently discovering which genes control which functions.
In your journal, predict what you think our knowledge of our DNA and genetics will have on the future?