in this ppt i tried to show how to draw pedigree chart , sorry for my mistakes., everything given are taken from internet,

1. PEDIGREE CHART
MEHEDI HASAN
The largest & oldest multispecialty eye hospital

2. WHAT IS A PEDIGREE CHART
A pedigree chart is a diagram that shows the occurrence and appearance of phenotypes of a
particular gene or organism and its ancestors from one generation to the next. It is also called
family tree.

3. How to draw pedigree
Males are represented as squares, while females are represented as circles
Shaded symbols mean an individual is affected by a condition, while an unshaded symbol means
they are unaffected
A horizontal line between man and woman represents mating and resulting children are shown
as offshoots to this line
Generations are labeled with roman numerals and individuals are numbered according to age
(oldest on the left)

4. Symbols of pedigree
Male family member is represented by a square
Female family member is represented by a circle
Gender not specified

5. Shaded circles or squares represents affected individuals
Affected fetus
Representation of 2 or more conditions

6. Individual seeking medical attention
Affected individual seeking medical attention

7. Normal relation between couple is demonstrated by straight line
Consanguineous mating is demonstrated by two Parallel lines
Divorced Relationship between couple is demonstrated by
broken line between the couple

8. Adopted child
Couple not having baby
Biological parents unknown
?

9. Twins
Identical Non-identical

10. Monozygotic
Dizygotic
Unknown zygocity
?

11. X-linked – Carrier are depicted Central dot in a circle
Autosomal carrier Represented by central vertical line
Deceased/Death sib is represented with slash
.

13. Example pedigree of an albinism patient

14. Determining Autosomal Inheritance
Autosomal Dominant
If both parents are affected and an offspring is unaffected, the trait must be dominant (parents
are both heterozygous)
All affected individuals must have at least one affected parent
If both parents are unaffected, all offspring must be unaffected (homozygous recessive)

15. Autosomal Recessive
If both parents are unaffected and an offspring is affected, the trait must be recessive (parents
are heterozygous carriers)
If both parents show a trait, all offspring must also exhibit the trait (homozygous recessive)

16. Determining X-Linked Inheritance
It is not possible to confirm sex linkage from pedigree charts, as autosomal traits could
potentially generate the same results. However certain trends can be used to confirm that a trait
is not X-linked dominant or recessive.

17. X-linked Dominant
If a male shows a trait, so too must all daughters as well as his mother
An unaffected mother cannot have affected sons (or an affected father)
X-linked dominant traits tend to be more common in females (this is not sufficient evidence
though)

18. X-linked Recessive
If a female shows a trait, so too must all sons as well as her father
An unaffected mother can have affected sons if she is a carrier (heterozygous)
X-linked recessive traits tend to be more common in males (this is not sufficient evidence
though)

19. In a Y-linked disorder, only males can be affected. If the father is affected all sons will be affected.
It also does not skip a generation.

20. In mitochondrial disorders it is only passed on if the mother is affected. If the mother is affected, all
offspring will be affected. If the father is affected, he does not pass it on to his offspring.

21. In an Autosomal Recessive Disorder, both parents can not express the trait, however, if both are carriers, their
offspring can express the trait. Autosomal recessive disorders typically skip a generation, so affected offspring
typically have unaffected parents. With an autosomal recessive disorder, both males and females are equally
likely to be affected.

22. Autosomal Dominant disorders don’t skip a generation, so affected offspring have affected parents. One
parent must have the disorder for its offspring to be affected. Both males and females are equally likely to
be affected, so it is an autosomal disorder.

23. In a X-linked Recessive Disorder, males are more likely to be affected than females. Affected sons typically
have unaffected mothers. The father also must be affected for daughter to be affected and the mother
must be affected or a carrier for the daughter to be affected. The disorder is also never passed from father
to son. Only females can be carriers for the disorders. X-linked recessive disorders also typically skip a
generation.

24. In a X-Linked Dominant disorder, if the father is affected all daughter will be affected and no sons will be
affected. It doesn’t skip a generation and if the mother is affected she has a 50% chance of passing it onto
her offspring.