1. Pedigrees

2. What is a Pedigree?
A pedigree is a diagram of family relationships that uses symbols to represent people and lines to represent genetic relationships. These diagrams make it easier to visualize relationships within families, especially large extended families.
Pedigrees are often used to determine the mode of inheritance (dominant, recessive) of genetic diseases.
Squares represent males.
Circles represent females.
Horizontal lines linking a
male and female represent
mating. Vertical lines
extending downward from
a couple represent their children.

3. If the purpose of a pedigree is to analyze the pattern of inheritance of a particular trait, it is usual to shade in this trait.
Infected male
In this pedigree: the grandparents
had three children, two boys and
one girl. The daughter married and
Produced two grandchildren, both
boys.
The grandfather has the trait. The daughter is a carrier. One of the grandsons has the trait.

4. Types of Inheritance
There are four types of inheritance patterns that we will be analyzing:
1. autosomal dominant
2. autosomal recessive
3. X – linked dominant
4. X- linked recessive

5. Autosomal Dominant Autosomal Recessive A – has the trait
a – normal (no trait, recessive)
Autosomal Recessive
A – normal ( no trait, recessive)
a – has the trait

6. X – Linked Dominant X – Linked Recessive Y – Y chromosome (males only)
XA – has the trait
Xa – normal
Y – Y chromosome (males only)
X – Linked Recessive
XA – normal
Xa – has the trait

7. Locus The location of a gene.
For example, the locus of the gene OCA1 (or Oculocutaneous
Albanism Type 1, the gene associated with albinism) is on
11q , which means it is on the long arm of chromosome
11, between sub-band 4 of band 1 to sub-band 1 of band 2.