1. What is genetics? 1 Every sex cell has one allele for each trait.
Genetics - the study of how traits are inherited through the interactions of alleles is

2. A tool used to show possible combinations of alleles
Genetics 1
Punnett Squares
How could you predict what the offspring would look like without actual mating?
Punnett square –
A tool used to show possible combinations of alleles

3. Alleles Determine Traits
Genetics 1
Alleles Determine Traits
Most cells in your body have two alleles for every trait.
These alleles are located on chromosomes within the nucleus of cells.

4. They show the genotype or genetic makeup, of an organism.
Genetics 1
Punnett Squares
They show the genotype or genetic makeup, of an organism.
The way an organism looks and behaves as a result of its genotype is its phenotype

5. An organism with two alleles that are the same is called homozygous
Genetics 1
Alleles Determine Traits
An organism with two alleles that are the same is called homozygous
An organism that has two different alleles for a trait is called heterozygous

6. Put names on top and side Put genotypes Cross top Cross bottom
Solving Punnet Squares
Draw box
Put names on top and side
Put genotypes
Cross top
Cross bottom
List genotypes (1 hetero Xx,)
List phenotypes (1 albino bird)
Calculate number out of 4 (1 of 4)
Calculate percentages (25%)

7. Genetics 1
Making a Punnett Square Dd D d DD dd

8. In a Punnett square, letters represent Dominant and recessive alleles.
Genetics 1
Punnett Squares
In a Punnett square, letters represent Dominant and recessive alleles. Dd D d DD dd

9. An Uppercase (D) letter stands for a dominant allele.
Genetics 1
Punnett Squares
An Uppercase (D) letter stands for a dominant allele.
A lowercase (d) letter stands for a recessive allele. Dd D d DD dd

10. Genetics Since Mendel 2
Incomplete Dominance
When the offspring of two homozygous parents show an intermediate phenotype, this inheritance is called incomplete dominance.
Examples of incomplete dominance include the flower color of some plant breeds and the coat color of some horse breeds.

11. The alleles for blood types are called A, B, and O.
Genetics Since Mendel 2
Multiple Alleles
Traits controlled by multiple alleles produce more than three phenotypes of that trait.
Blood type in humans is an example of multiple alleles that produce only four phenotypes.
The alleles for blood types are called A, B, and O.

12. Genetics Since Mendel 2
Multiple Alleles
When a person inherits one A allele and one B allele for blood type, both are expressedphenotype AB.
A person with phenotype A blood has the genetic makeup, or genotypeAA or AO.

13. Someone with phenotype B blood has the genotype BB or BO.
Genetics Since Mendel 2
Multiple Alleles
Someone with phenotype B blood has the genotype BB or BO.
Finally, a person with phenotype O blood has the genotype OO.

14. 2 Multiple Alleles Genetics Since Mendel Allele O is recessive
A and B are dominant
Father type AB phenotype A B
Mother type B
phenotype AB
Called AB BB
Called B

15. 2 Multiple Alleles Genetics Since Mendel Allele O is recessive
A and B are dominant
Father type A phenotype A
Can only be
Ao or AA o
Mother type B
phenotype B AB
Called AB Bo
Called B Ao
Called A oo

16. Genetics Since Mendel 2
Multiple Alleles
When a person inherits one A allele and one B allele for blood type, both are expressedphenotype AB.
A person with phenotype A blood has the genetic makeup, or genotypeAA or AO.

17. Someone with phenotype B blood has the genotype BB or BO.
Genetics Since Mendel 2
Multiple Alleles
Someone with phenotype B blood has the genotype BB or BO.
Finally, a person with phenotype O blood has the genotype OO.

18. 2 Multiple Alleles Genetics Since Mendel Allele O is recessive
A and B are dominant
Father type AB phenotype A B
Mother type B
phenotype AB
Called AB BB
Called B

19. 2 Multiple Alleles Genetics Since Mendel Allele O is recessive
A and B are dominant
Father type A phenotype A
Can only be
Ao or AA o
Mother type B
phenotype B AB
Called AB Bo
Called B Ao
Called A oo

20. 2 Multiple Alleles Genotype Phenotype Ao or AA A Bo or BB B AB oo o
Genetics Since Mendel 2
Multiple Alleles
Genotype
Phenotype
Ao or AA A
Bo or BB B AB oo o
Note in blood typing
there is only one recessive – type o
The A or B are dominant – which why it is called multiple alleles

21. Pedigrees Trace Traits
Genetics Since Mendel 2
Pedigrees Trace Traits
A pedigree is a visual tool for following a trait through generations of a family.
Males are represented by squares and females by circles.

22. Child
Child
Note children and genetic/blood relatives are connected by the direct white line

23. Pedigrees Trace Traits
Genetics Since Mendel 2
Pedigrees Trace Traits
A completely filled circle or square shows that the trait is seen in that person.
Half-colored circles or squares indicate carriers.
People represented by empty circles or squares do not have the trait and are not carriers.

24. A pedigree is a useful tool for a geneticist.
Genetics Since Mendel 2
Using Pedigrees
A pedigree is a useful tool for a geneticist.
When geneticists understand how a trait is inherited, they can predict the probability that a baby will be born with a specific trait.

25. Pedigrees also are important in breeding animals or plants.
Genetics Since Mendel 2
Using Pedigrees
Pedigrees also are important in breeding animals or plants.
These organisms are bred to increase their
yield and nutritional content.

26. Each egg produced by a female normally contains one X chromosome.
Genetics Since Mendel 2
Sex Determination
Each egg produced by a female normally contains one X chromosome.
Males produce sperm that normally have either an X or a Y chromosome.

27. Genetics Since Mendel 2
Sex Determination
When a sperm with an X chromosome fertilizes an egg, the offspring is a female, XX.
A male offspring, XY is the result of a Y-containing sperm fertilizing an egg.

28. Genetics Since Mendel 2
Chromosome Disorders
If three copies ( an extra ) of chromosome 21 are produced in the fertilized human egg, Down’s syndrome results.

29. Recessive Genetic Disorders
Genetics Since Mendel 2
Recessive Genetic Disorders
Cystic fibrosis is the most common Recessive genetic disorder
Can lead to death among Caucasian Americans.

30. Impact of the Environment
Genetics Since Mendel 2
Impact of the Environment
Your environment plays a role in how some of your genes are expressed or whether they are expressed at all.
Environmental influences can be internal or external.
Genes determine many of your traits, you might be able to influence their expression by the decisions you make.
Some genetically people at risk for skin cancer limit their exposure to the Sun and take care of their skin, they might never develop cancer.

31. Biotechnology 3
Genetic Engineering
Through genetic engineering, scientists are experimenting with biological and chemical methods to change the arrangement of DNA that makes up a gene.
Genetic engineering already is used to help produce large volumes of medicine.

32. Biotechnology 3
Genetically Engineered Plants
Genetic engineering can produce improvements in crop plants, such as corn, wheat, and rice.
One type of genetic engineering involves finding the genes that produce desired traits in one plant and then inserting those genes into a different plant.