Pedigrees
-
Upload
ebony-bowen -
Category
Documents
-
view
29 -
download
0
description
Transcript of Pedigrees
PedigreesPedigreesA tool used to track the inheritance
of traits through a family.
Symbols used by Geneticists
Pedigree SymbolsPedigree Symbols
Male Female
Does not show Trait
Shows Trait
Carrier (heterozygote)
Died from the trait
Reading PedigreesReading Pedigrees
In a pedigree, a circle represents a female; a square represents a male.
Female Male
?
I
II
III
IV
1 2
1
1
1
32
2
2
4
3
3
5
4
4 5
Highlighted circles and squares represent individuals showing the trait being studied.
?
I
II
III
IV
1 2
1
1
1
32
2
2
4
3
3
5
4
4 5
Reading PedigreesReading Pedigrees
Reading PedigreesReading Pedigrees
?
I
II
III
IV
1 2
1
1
1
32
2
2
4
3
3
5
4
4 5
Circles and squares that are not highlighted designate individuals that do not show the trait.
1 2
1
1
1
32
2
2
4
3
3
5
4
4 5
?
I
II
III
IV
A horizontal line connecting a circle and a square indicates that the individuals are parents, and a vertical line connects parents with their offspring.
Reading PedigreesReading Pedigrees
A half-shaded circle or square represents a carrier, a heterozygous individual.
Reading PedigreesReading Pedigrees
Reading PedigreesReading Pedigrees
Each horizontal row of circles and squares in a pedigree designates a generation, with the most recent generation shown at the bottom.
1 2
1
1
1
32
2
2
4
3
3
5
4
4 5
?
I
II
III
IV
Reading PedigreesReading Pedigrees
1 2
1
1
1
32
2
2
4
3
3
5
4
4 5
?
The generations are identified in sequence by Roman numerals, and each individual is given an Arabic number.
I
II
III
IV
Queen Victoria, Prince Albert and their 9 Children
Victoria
Edward
AliceAlfred
Helena
LouiseArthurLeopold
Beatrice
Hemophelia Genes
XHXH = Female, normal
XHXh = Female, carrier
XhXh = Female, hemophiliac
XHY = Male, normal
XhY = Male, hemophiliac
Show the cross of…• A woman who is a carrier marries a normal man.
• What is the probability that their children will have the disease? What sex will a child in the family with hemophilia be?