The Human Genome
Chapter 12
Karyotypes and Pedigrees
The Human Genome

In humans, diploid (2n) = 46
 That
 44
means somatic cells have 46 chromosomes
autosomal chromosomes and a pair of sex
chromosomes
Pedigrees

A pedigree is a diagram that traces a single trait
through several generations
Individuals shaded in have attached earlobes. Is this trait
dominant or recessive?
RECESSIVE!! Partially shade carriers and label genotypes
Solution:
A Pedigree for a sex-linked recessive
trait:
Shade in known carriers and label genotypes.
Solution:
The Human Genome
Chapter 12
Blood Typing and Chromosomal Genetic Disorders
Use only to type blood in lab
(serum reacts to antigens present)
Blood Typing Chart
Blood
Type
A
B
AB
O
Rh+
Rh-
Genotypes
Antigens
Antibodies
Donate to
Receive
from
Reaction to
Anti-A
Reaction to
Anti-B
Reaction to
Anti-Rh
Use only to type blood in lab
(serum reacts to antigens present)
Blood Typing Chart
Blood
Type
Genotypes
A
IAIA, IAi
B
IBIB, IBi
AB
IAIB
O
ii
Rh+
++, +dominant
Rh-
-recessive
Antigens
Antibodies
Donate to
Receive
from
Reaction to
Anti-A
Reaction to
Anti-B
Reaction to
Anti-Rh
Use only to type blood in lab
(serum reacts to antigens present)
Blood Typing Chart
Blood
Type
Genotypes
Antigens
Antibodies
A
IAIA, IAi
A
Anti-B
B
IBIB, IBi
B
Anti-A
AB
IAIB
AB
none
O
ii
none
Anti-A
Anti-B
Rh+
++, +dominant
Rh
none
Rh-
-recessive
none
*only if
exposed to
antigen
Donate to
Receive
from
Reaction to
Anti-A
Reaction to
Anti-B
Reaction to
Anti-Rh
*Rh- mothers can be
exposed to the Rh
antigen if the fetus is
Rh+
Use only to type blood in lab
(serum reacts to antigens present)
Blood Typing Chart
Blood
Type
Genotypes
Antigens
Antibodies
Donate to
Receive
from
A
IAIA, IAi
A
Anti-B
A,AB
A,O
B
IBIB, IBi
B
Anti-A
B,AB
B,O
AB
IAIB
AB
none
AB
AB,A,
B,O
O
ii
none
Anti-A
Anti-B
A,B,
AB,O
O
Rh+
++, +dominant
Rh
none
pos
pos or
neg
Rh-
-recessive
none
*only if
exposed to
antigen
pos or
neg
neg
only
Reaction to
Anti-A
Reaction to
Anti-B
Reaction to
Anti-Rh
*Rh- mothers can be
exposed to the Rh
antigen if the fetus is
Rh+
Use only to type blood in lab
(serum reacts to antigens present)
Blood Typing Chart
Blood
Type
Genotypes
Antigens
Antibodies
Donate to
Receive
from
Reaction to
Anti-A
Reaction to
Anti-B
Reaction to
Anti-Rh
A
IAIA, IAi
A
Anti-B
A,AB
A,O
clumps
-
B
IBIB, IBi
B
Anti-A
B,AB
B,O
-
clumps
AB
IAIB
AB
none
AB
AB,A,
B,O
clumps
clumps
O
ii
none
Anti-A
Anti-B
A,B,
AB,O
O
-
-
Rh+
++, +dominant
Rh
none
pos
pos or
neg
clumps
Rh-
-recessive
none
*only if
exposed to
antigen
pos or
neg
neg
only
-
*Rh- mothers can be
exposed to the Rh
antigen if the fetus is
Rh+
Nondisjunction
Occurs when a chromosome
or chromosomes fail to
separate in meiosis
 Individuals end up with the
wrong number of
chromosomes ( < or > 46
total)
 Risk factor increases with age

Nondisjunction of Autosome

Down Syndrome
caused by trisomy 21 (3 copies of
chromosome #21)
Nondisjunction of Sex Chromosomes

Turner Syndrome (karyotype 45,
XO):
Female; sterile; sex organs do not
develop at puberty

Klinefelter’s Syndrome (Karyotype
47, XXY):
Male; infertility; fewer secondary
sex characteristics; variations are
48, XXXY and 49, XXXXY