1. Chapter 6, Section 1
Human Inheritance

2. Patterns of Human Inheritance
The traits you get from both your mother’s side of the family and your father’s side
a single gene with one dominant and one recessive allele, for example, widow’s peak
These traits have two different phenotypes (physical appearances)
Inheritance
Some human traits are controlled by:
See Brain Pop – “Heredity”
A - dominant allele for widow’s peak
a - recessive allele for straight hairline
Both parents are heterozygous for widow’s peak (Aa)

3. Other human traits are controlled by:
Single genes with multiple alleles
For example, blood has 3 alleles: i, IA, and IB
It’s the combination of these alleles that determines your blood type

4. The genes act together as a group to produce a single trait
Many genes
For example, height, skin, and hair color
The genes act together as a group to produce a single trait
Finally, other human traits are controlled by:

5. Table Talk: (Summarize) What are the three patterns of inheritance that control human traits?
1. A single gene with one dominant
and one recessive allele 2. Single genes with multiple alleles 3. Many genes

6. Sex Chromosomes One of the 23 pairs of chromosomes in each body
They determine whether a person is male (XY) or female (XX)
They also carry genes that determine other traits (for example, color blindness is more common in males)
See Brain Pop “Gender Determination”

7. a picture of all the chromosomes in a cell
Karyotype
a picture of all the chromosomes in a cell
used to diagnose genetic disorders, such as Down syndrome
TABLE TALK: Is this the karyotype of a male or female?

8. Quick Write: What is the difference between genotype, phenotype and karyotype?

9. Genes and the environment
Many of an organism’s characteristics are determined by an interaction between both
Examples: diet can affect height; opportunities to play sports can affect athletic ability

10. Selective Breeding
The process of selecting organisms with desired traits to be the parents of the next generation
TABLE TALK: Do you think people should have the ability to genetically choose what their children should look like? Explain
See Discovery Education video, “Biologically Speaking – Genetics & Heredity” 16 min.
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