Transcript Chapter 14: Human Heredity

Autosomal Recessive Inheritance
• Characteristics of autosomal
recessive inheritance:
– no difference in expression
between males and females
– matings between affected
individuals produce
100% affected offspring
– Affected genotype (filled in
shape) must be “dd”
– Unaffected genotypes (empty
shapes) can be either
“DD” or “Dd”
Autosomal Recessive Inheritance
• Characteristics of autosomal
recessive inheritance:
– no difference in expression
between males and females
– matings between affected
individuals produce
100% affected offspring
– Affected genotype (filled in
shape) must be “dd”
– Unaffected genotypes (empty
shapes) can be either
“DD” or “Dd”
Must be “Dd”
Must be “dd”
For the rest of the people you cannot be
sure if they are “DD” or “Dd”.
Autosomal Dominant Inheritance
• Characteristics of autosomal dominant inheritance:
– no difference in expression between
males and females
– no unaffected heterozygous individuals
– does not skip generations
– Affected genotypes (filled in shapes) can be
either “Dd” or “DD”
– Unaffected genotype (empty shape) must be “dd”
Autosomal Dominant Inheritance
• Characteristics of autosomal dominant inheritance:
– no difference in expression between
males and females
– no unaffected heterozygous individuals
– does not skip generations
– Affected genotypes (filled in shapes) can be either “Dd” or “DD”
– Unaffected genotype (empty shape) must be “dd”
Must be “Dd”
All empty shapes
must be “dd”
Must be “Dd”
Sex-linked (X-linked) recessive inheritance
•
Characteristics of sex-linked (Xlinked) recessive inheritance:
– most affected individuals will
be male
– affected females must have
an affected father and either
a heterozygous or affected
mother
– affected females will have
100% affected sons
– tends to skip generations
– Affected genotypes (filled in
shapes) must be “XdXd ” or
“XdY”
– Unaffected genotypes
(empty shapes) can be
“XDXD ”, “XDXd ”, or “XDY”
Sex-linked (X-linked) recessive inheritance
•
Characteristics of sex-linked (Xlinked) recessive inheritance:
– most affected individuals will
be male
– affected females must have
an affected father and either
a heterozygous or affected
mother
– affected females will have
100% affected sons
– tends to skip generations
– Affected genotypes (filled in
shapes) must be “XdXd ” or
“XdY”
– Unaffected genotypes
(empty shapes) can be
“XDXD ”, “XDXd ”, or “XDY”
XDY
XDXd
XdY
XDY
XD_
XD_
XdY
XD_
XDXd
Sex-linked (X-linked) Dominant Inheritance
• Characteristics of sexlinked (X-linked) dominant
inheritance:
– affected males must have
affected mothers
– affected females must
have one affected parent
– affected males will have
100% affected daughters
– affected females are
expected to produce half
normal, half affected
offspring
– Affected genotypes (filled
in shapes) can be “XDXD ”,
“XDXd ”, or “XDY”
– Unaffected genotypes
(empty shapes) must be
“XdXd ” or “XdY”
Sex-linked (X-linked) Dominant Inheritance
• Characteristics of sexlinked (X-linked) dominant
inheritance:
– affected males must have
affected mothers
– affected females must
have one affected parent
– affected males will have
100% affected daughters
– affected females are
expected to produce half
normal, half affected
offspring
– Affected genotypes (filled
in shapes) can be “XDXD ”,
“XDXd ”, or “XDY”
– Unaffected genotypes
(empty shapes) must be
“XdXd ” or “XdY”
XdXd
XdY
XDXd
XDY
XDXd
XDY
XdXd
XDXd