Page 40 - CB1.3 Genetic Varation sciPAD

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40 CB 1.3 GENETIC VARIATION
TRACKING GENES
Pedigree Charts
A ‘pedigree chart’ is like a family tree that shows the genetic relationships among members of the
same family. It can be used to track genes through many generations.
By analysing a pedigree chart, we can determine genotypes, identify phenotypes, and predict
how a trait will be passed on in the future. The information from a pedigree chart makes it possible
to determine how certain alleles are inherited and whether they are dominant or recessive.
Pedigree charts are particularly useful to examine the inheritance pattern of genetic diseases.
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II
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Horizontal lines
indicate breeding
pairs and mating.
Vertical lines
indicate offspring.
Shaded symbols mean
an individual is affected
by a condition.
Circles are usually used to
symbolise females.
Squares are usually used to
symbolise males.
Generations are labelled
with roman numerals.
1. Use the space below to draw a pedigree chart for your family. Try and go back at least
three generations.
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