1. Genetics
Chapters 9 and 12

2. Introduction to Genetics
Genetics is the science of heredity and variation in living organisms.
Every living thing has inherited a set of characteristics from its parent or parents.
Traits – genetically determined variant of a characteristic
Francis Crick's first sketch of the deoxyribonucleic acid double-helix

3. Introduction to Genetics
At its most fundamental level, inheritance in organisms occurs by means of discrete traits, called “genes”.
This property was first observed by
Gregor Mendel
Chapter 12: Day One

4. Introduction to Genetics
The molecular basis for genes is: deoxyribonucleic acid.
Good thing to know.
DNA
Chapter 12: Day One

5. Gregor Mendel
Called the father of genetics for his study of the inheritance of traits in pea plants.
Augustinian priest and scientist
Mendel showed that the inheritance of traits follows particular laws, which were later named after him.
The significance of Mendel's work was not recognized until the turn of the 20th century.
Its rediscovery prompted the foundation of the discipline of genetics.
Chapter 11: Day Five Start Here

6. Gregor Mendel Used garden peas and studied 7 specific traits
These different varieties of peas are called true-breeding because they always pass on their traits to their offspring
Chapter 11: Day Five

7. Gregor Mendel
Normally the flowers of pea plants self-pollinate: the pollen (male sex cells) and the ovum (female sex cells) come from the same flower
pollen
If Mendel’s true-breeding plants were allowed to self-pollinate, the plants would inherit all the characteristics from the plant that bore them
ovum
Chapter 11: Day Five

8. Gregor Mendel He studied 7 specific traits
Each trait had 2 possible forms (alleles)
Allele- one of a number of different forms of a gene

9. P generation Cross P generation Original true-breeding plants
F1 generation
Hybrid plants- offspring that have inherited 1 trait from each parent r r r r
Chapter 11: Day Five

10. Why are the F2 hybrids all red?
P generation Cross
Why are the F2 hybrids all red?
Mendel concluded that each P1 parent had 2 identical genes for each trait AND that 1 allele must be DOMINANT and the other RECESSIVE r r r r r r
Chapter 11: Day Five

11. Genotype- the letter combinations showing possible alleles
Identical alleles are homozygous
Opposite alleles are heterozygous
Phenotype is the form of the trait that shows up in what the organism looks like
rr = homozygous white
RR = homozygous red
Rr = heterozygous red
red
white or
Chapter 11: Day Five

12. 3:1 ratio F1 generation F2 generation 3:1 ratio, why is that? r r r r
Chapter 11: Day Five

13. When each F1 plant flowers and produces gametes, the 2 alleles segregate from each other so that each gamete carries only a single copy of each gene.
Therefore, each F1 plant produces 2 types of gametes- those with the allele for redness and those with the allele for whiteness.

14. Mendel’s Results & Conclusions
Law of Segregation – a pair of factors is segregated, or separated, during the formation of gametes
Law of Independent Assortment - factors separate independently of one another during the formation of gametes

15. Gregor Mendel Review
The inheritance of biological characteristics is determined by individual units known as genes. Genes are passed from parents to their offspring.
The principle of dominance states -some alleles are dominant and some others are recessive.
During gamete formation, alleles segregate from each other so that each gamete carries only a single copy of each gene.
Principle of independent assortment –alleles segregate independently

16. Inheritance Pattern and Human Genetics
Chapter 12

17. Chromosomes Sex chromosomes Autosomes
Contain genes that determine the sex of an individual
Autosomes
All the other chromosomes
This is old news.

18. Sex Determination

19. Sex-Linked Trait
A trait that is coded for an allele on a sex chromosome
Is something missing here? r
Bigger, has more information
Most X-linked alleles have no counterpart on the Y chromosome.

20. Dude, I ain’t going nowhere!!
Linked Genes
Pairs of genes that tend to be inherited together, found on same chromosome
Don’t leave me, man!!
Dude, I ain’t going nowhere!!

21. Chromosome Map
A diagram that shows the linear order of genes on a chromosome.

23. Mutations A change in the nucleotide-base sequence.
Involve an entire chromosome or a single nucleotide.
Germ cell:
Occurs in the organism’s gametes. Passed onto offspring.
Somatic-cell:
Take place in organism’s own body cell
Lethal:
Cause death.

24. Chromosome Mutations Deletion Inversion Translocation Nondisjunction
Loss of a piece of chromosome
Inversion
Segment breaks off, flips, and reattaches
Translocation
Piece breaks off and reattaches to different chromosome
Nondisjunction
Chromosome fails to separate from its homologous partner during meiosis

25. Gene Mutations Point mutations Substitution Frameshift mutation
Change that occurs within a single gene or other DNA segment
Substitution
One nucleotide replaces another
Frameshift mutation
Loss of nucleotides cause incorrect grouping of codons
Insertion mutation
One or more nucleotides are added to a gene, which can also result in a frameshift mutation
See page 240

26. Pedigree
A diagram that shows how a trait is inherited over several generations.

27. Genetic Traits and Disorders
Genetic disorders
Diseases or disabling conditions that have a genetic basis
Complex characters
Characters that are influenced strongly by the enviroment and by genes

28. Beyond Gregor Mendel
Some alleles are neither dominant nor recessive, and many traits are controlled by multiple alleles or multiple genes.
Incomplete dominance
Codominance
Multiple alleles
Polygenic traits

29. Polygenic
Characteristics are influenced by several genes

30. Multiple Alleles
Genes with 3 or more alleles

31. Codominance
Both alleles are expressed

32. Incomplete Dominance
A trait that is blended

33. Cloned glow in the dark cats.
Genetic Engineering
Genetic engineering, recombinant DNA technology, genetic modification/manipulation (GM) and gene splicing are terms that are applied to the direct manipulation of an organism's genes.
Cloned glow in the dark cats.
Chapter 13: Day Seven

34. Genetic Engineering
There are a number of ways through which genetic engineering is accomplished. Essentially, the process has four main steps.
1) Isolation of the gene of interest
2) Insertion of the gene into a vector
3) Transformation of cells of organism to be modified
4) Tests to isolate genetically modified organism (GMO)
Chapter 13: Day Seven

35. Lab Assignment
In your team, begin discussion on what you think genetic engineering is and your position on stem cell research.
AFP / Getty Images
Chapter 13: Day Seven Stop Here