PATTERNS OF HEREDITY
Group 3
Queen Noga Tour, King Kadison
Feldman, Princess Maddy Gotta, Prince
Tinka Peterka, Grange
Human Heredity
• Karyotype- photograph of
chromosomes grouped in order in pairs
• Sex chromosomesdetermine an individuals
sex (XX for females, XY for males)
• Autosomes- chromosome that is not a sex
chromosomes. (44 autosomes)
Human Traits & Pedigrees
Males
Females
• Pedigree- chart that shows family
relationships; used to track inheritance of
certain traits.
• Horizontal lines represent mating
• Vertical lines represent offspring
• Shaded shapes have the trait
Autosomal Dominant- shaded individuals HAVE the trait & must have the DOMINANT
allele (at least one capital letter)
tt
Tt
TT
Tt
Human Traits & Pedigrees
• Autosomal Recessive- shaded individuals
HAVE the trait & they are homozygous
recessive (2 lowercase letters)
Tt
Tt
tt
T?
• The function of genes is to tell the cell to make proteins
• DNA is packaged into chromosomes
• Our genes encode the instructions that define our traits
Vocab:
1. Complex traits- traits that are shaped by more than one
genes
2. Allele- a form of a gene which codes for one possible
outcome of a phenotype
–
Individuals only have 2 alleles (one from their mother, one from their
father)
3. Polygenic- the inheritance pattern of a trait that is controlled
by two or more genes, which may have more than one
alleles
Human Blood Types
•
There are 3 alleles for the gene that determines blood type
Allele
IA
IB
I
Type A Genotypes: IAIA , Iai
Type B Genotypes: IBIB, Ibi
Type AB Genotype: IAIB
Type O Genotype: ii
Codes for…
Type A
Type B
Type O
Sex-Linked Traits
•
Designating Sex-Linked Traits
– XA = normal
– Xa = possesses the trait
– Y = neutral
Genotype
Phenotype
X AX A
Normal female
X AX a
Normal female; carrier
X aX a
Female w/ trait
XAY
Normal Male
Xa Y
Male w/ trait
– X-linked traits may skip generations
– Affects males more often than females because they only have one X chromosome
Multiple Alleles
• Allele- form of a gene which codes for one
possible outcome of a phenotype
• There may be multiple alleles in a population,
but individuals have only 2 of them
• Half of genes are inherited from mom and half
are inherited from dad, so we end up with 2
alleles for every trait
Incomplete Dominance
In Blood type
Genotype
Resulting blood type
IAi=Homozygous
IAi= Type A
ii= heterozygous
Ii- Type O
IBii = Homozygous
IBi = Type B
When 2 heterozygous blood types combine, they create a
new blood type.
Co-dominance in Blood type
Genotype
Resulting Blood type
IAIA = homozygous dominant
IAIA= Type A
IAIB = heterozygous
IAIB= Type AB
IBIB= homozygous dominant
IBIB =Type B
• When Both blood types are dominant, a new blood
type is formed
Questions
Fill in the pedigree
a. TT
b. Tt
c. tt
d. T?
1
3
8
4
9
2
5
6
10
7
11
12
Fill in the Pedigree
a.
b.
c.
d.
e.
f.
XAXA
XAXa
XaXa
XAY
XaY
XAX?
13
15
14
16
17
18) A couple has a baby. The man has blood
type O, and the woman has blood type AB.
What blood types can the baby have?
a. Type O and AB
b. Type A and B
c. Type O
d. Type A and O
19) How many men w/ressisive trait are in this
un colored pedigree?
TT
tt
Tt
TT
Tt
a.6
b.0
c.1
d.4
tt
Tt
Tt
TT
Tt
TT
ANSWERS
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
12)
C
B
B
B
C
B
C
D
C
C
B
B
MORE ANSWERS
13)B
14)D
15)F
16)E
17)F
18) B
19) D