1. Following Patterns of Inheritance in Humans
Chapter 5 ~ Section 5.3
Following Patterns of Inheritance in Humans

2. Review - Key Ideas Section 5.1 Section 5.2
Mendel’s experiment with Pea Plants = Dominant & Recessive Traits
Monohybrid Cross
Mendel’s Law of Segregation
Differences between genotype & phenotype
Section 5.2
Use of Punnett Squares to analyze and predict the inheritance of traits
Law of Independent Assortment
Dihybrid Crosses
9:3:3:1
Chromosome Theory of inheritance

3. Introduction
Controlled breeding of plants & animals has allowed scientists and researchers to come across many genetic discoveries
Breeding experiments are NOT ethical or possible for human genetics
So they use a flow chart called a Pedigree to illustrate inheritance patters with colours and symbols between generations

4. 411 on Pedigrees
Is a way to analyze how a trait “runs in the family”
Used by geneticists to determine patterns of inheritance of a particular trait that is controlled by a 1 or more genes
Help uncover the genotype of a particular member of a family
Can be used with a Punnett Square to determine the probability of a specific genotype / phenotype in an offspring
Mainly used to determine the presence / absence of an allele linked to a disease

5. 411 on Pedigrees

6. Autosomal Inheritance
Autosomal Chromosomes = any chromosomes other than Sex chromosome
Autosomal Inheritance = the traits that are found on autosomal chromosomes (1 to 22)
Autosomal genes are also responsible for many inherited disorders
which can be classified as autosomal Dominant or Recessive

7. Autosomal Inheritance

8. Autosomal Inheritance: Dominant
A pedigree can determine whether the inheritance pattern of a disorder is dominant or recessive
You can have both parents affected by a gene (heterozygous dominant) and yet their child may not be (homozygous recessive)

9. Autosomal Inheritance: Recessive
In order for someone to have an autosomal recessive disorder, BOTH their parents must be carriers of the disorder, via:
Heterozygous dominant (Aa)
Homozygous recessive (aa)
People who are heterozygous (Aa) for a disorder are not first hand affected by it, even though they are “carriers”

10. Genetic Testing
There are lots of different ways individuals who are at risk of developing genetic disorders, or of passing these disorders on to their off spring can be tested
Once geneticists are able to identify the chromosome and eventually the gene responsible for a disorder, more detailed analyses are possible

11. Types of Genetic Tests – pg. 224
Method
What is Analyzed
Example
Karyotype
Chromosome Structure
Chromosome Number
F.I.S.H
Details of chromosome abnormalities
Target a specific region on a chromosome
Gene Testing
Mutation (s) in the DNA sequence of a gene
Biochemical Testing
Abnormal enzymes and proteins are visible due to mutation in protein synthesis

12. Genetic Testing At work
Read pgs
Explain the genetic defects of Huntington’s Disease and Cystic Fibrosis
Explain how genetic testing was used to identify them

13. Genetic Testing At work
Huntington’s Disease
Cystic Fibrosis

14. Genetic Counsellors
Are a health care professional with specialized training in human genetics and in counselling people and their families who may have or be at risk for a genetic disorder
They too use Pedigrees to determine the genotypes of family members and provide options for genetic testing to explain the possibility of them passing on a disorder to their children

15. Gene Therapy: A Cure for Genetic Disorders?
While genetic testing give people options for people carrying a genetic disorder, their greatest HOPE can lie within gene therapy
Gene Therapy – a technique aimed at correcting the effects of a mutated gene that’s related to a disorder by introducing the correct form of the defected gene in a patient’s genome

16. Gene Therapy: A Cure for Genetic Disorders?
Works by having a copy of the NORMAL gene inserted into a vector , who carries the gene into the cell
Once inside, the correct protein can be made from the right information!

17. Gene Therapy: A Cure for Genetic Disorders?

18. The Future of gene Therapy
Researchers have been working with Gene Therapy since 1990 – yet is still very “experimental”
This is because of 2 reasons:
Use of viruses to send the right gene onto the cell can sometimes be “attacked” by the immune system as it is a virus & foreign to the cell
Benefits are Short-lived
Difficulty integrating the correct gene into the cell’s chromosomes, which means the correct gene does not reproduce / fix the problem

19. STSE: Gene Therapy Case Study – p. 232