Download Patterns of Inheritance

Karyotype & Sex Genes
Objective 1 & 7
Karyotype

Picture of all 46
chromosomes

23 pairs
Karyotype includes:
 44 autosomes
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Pair 1-22
2 sex chromosomes
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XX female
XY male
Sex Linked Genes


Sex linked genetic defects
are the most common type
of defects and are FAR more
common in males
We have 2 of each
chromosome so if there’s a
problem in one chromosome,
we have a backup.
Sex Chromosomes
Sex Linked Genes


Men do not have any
backup chromosomes for
sex (only 1 X and 1 Y)
So if there’s a problem on
one, men will develop that
problem (baldness, color
blindness, etc.)
Sex Chromosomes
Example

Baldness is sex linked:
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R normal hair (RR, Rr)
r baldness (rr)
Both R and r are found on the X chromosome
Female: XRXR = ?
XRXr = ?
XrXr = ?
Male:
XRY = ?
XrY = ?