honors biology ch. 11 complex inheritance and human heredity complex inheritance and human heredity
TRANSCRIPT
Honors BiologyCh. 11
Honors BiologyCh. 11
Complex Inheritanceand Human
Heredity
Complex Inheritanceand Human
Heredity
I. Human InheritanceI. Human Inheritance- heredity in humans is the same as
in other organisms- most genetic diseases are
recessive and rare
A. Recessive TraitsA. Recessive Traits- diseases caused by a single
defective gene/protein1. Cystic Fibrosis (CF)2. Tay-Sachs Disease3. Albinism4. Phenylketonuria (PKU)5. Sickle-Cell Anemia
DISORDEROCCURRENC
E IN THE U.S.
CAUSE EFFECTCURE-
TREATMENT
Cystic Fibrosis
1 : 3500(Mainly people of northern European descent)
The gene that codes for a membrane protein is defective.
*Excessive Mucus Production
*Digestive and Respiratory Failure
*No Cure*Daily
Cleaning of Mucus from Lungs
*Mucus-thinning Drugs
Albinism 1 : 17,000 Genes do not produce melanin.
*No Color in Skin, Eyes & Hair
*Prone to Skin Cancer and Cataracts
*No Cure*Protect
Skin from the Sun
Tay-Sachs Disease
1 : 2500 (Affects People of Jewish descent)
Absence of a necessary enzyme that breaks down fatty substances
*Buildup of Fatty Deposits in The Brain
*Mental Disabilities
*No Cure or Treatment
*Death Occurs by Age 5
B.Dominant Traits B.Dominant Traits 1. Huntington’s Disease
- rare, degenerative nervous system disorder
Woody Guthrie
2. Achondroplasia2. Achondroplasia- a disorder of
bone growth- homozygous
dominant condition is fatal
3. Polydactyly3. Polydactyly
II. Other Inheritance Patterns
II. Other Inheritance PatternsA.A. Sex Sex Chromosomes:Chromosomes:
- pair of chromosomes that determine an
individual’s sex XX - female XY -
male
Autosomes: the other chromosome pairs except the sex chromosomes
Human Chromosomes:44 Autosomes
Human Chromosomes:44 Autosomes
Human Chromosomes:
2 Sex Chromosomes
Human Chromosomes:
2 Sex Chromosomes
B.Sex-Linked Traits: B.Sex-Linked Traits: - trait controlled by a recessive
allele on the "X" sex chromosome- more common in males- Ex. Red-green color-blindness,
hemophilia
Can you see a number?
Can you see a number?
Queen Victoria’s Family
Queen Victoria’s Family
Pedigree of Europe’s Royal Families
Pedigree of Europe’s Royal Families
C. Sex-Influenced Traits:
C. Sex-Influenced Traits:
- trait controlled by an allele that is recessive in females and dominant in males
- Ex. Male-pattern Baldness
D. Incomplete Dominance:
D. Incomplete Dominance:- a trait in which the
heterozygote shows a blending of traits
- Ex. Carnations and Snap dragons: R - red, W - white, RW - pink
RR RR
Incomplete Incomplete Dominance: PDominance: PIncomplete Incomplete Dominance: PDominance: P
Homozygous Red Parent
Homozygous White Parent RW
RWRW
RW
Pink Pink
Pink Pink
W
W
RR WW
Incomplete Dominance: F1
Incomplete Dominance: F1
HeterozygousPink Parent
Heterozygous Pink Parent RW
RWR R
WW
Red Pink
Pink White
WW
RR
E.Codominance:E.Codominance:- a trait in which the heterozygote
shows both alleles equally- Ex. Horses:
R - red, W - white, RW - roan- Ex. ABO Blood Groups
A B AB
E.Codominance:E.Codominance:
Roan HorsesRoan Horses
E.Codominance:E.Codominance:
ABO Blood Groups
ABO Blood Groups
F.F. Polygenic Polygenic Inheritance:Inheritance:
F.F. Polygenic Polygenic Inheritance:Inheritance:- traits controlled by more than
one pair of genes- Ex. hair, skin, and eye color
ABAB
AbAb
aBaB
abab
ABAB AbAb aBaB abab Human Eye Color
Human Eye Color
EGGSEGGS
SP
ER
MS
PE
RM
MotherMother
AaBbAaBb
FatherFather
AaBbAaBb
AABBAABB AABbAABb AaBBAaBB AaBbAaBb
blackblack dark browndark brown dark browndark brown light brownlight brown
AAbBAAbB
dark browndark brown
AAbbAAbb
light brownlight brown
AabBAabB
light brownlight brown
AabbAabb
blueblue
aABBaABB aABbaABb aaBBaaBB aaBbaaBb
dark browndark brown light brownlight brown light brownlight brown blueblue
aABbaABb aABbaABb aaBbaaBb aabbaabb
light brownlight brown blueblue blueblue light bluelight blue
Human Skin ColorHuman Skin Color
G.Epistasis G.Epistasis - A gene at one locus alters the
phenotypic expression of a gene at a second locus.
- Example: black, brown, and white coat in mice
Epistasis: Black, Brown, and White
Coat in Mice
Epistasis: Black, Brown, and White
Coat in Mice
BC bC Bc bc1⁄41⁄41⁄41⁄4
BC
bC
Bc
bc
1⁄4
1⁄4
1⁄4
1⁄4
BBCc BbCc BBcc Bbcc
Bbcc bbccbbCcBbCc
BbCC bbCC BbCc bbCc
BBCC BbCC BBCc BbCc
9⁄163⁄16
4⁄16
BbCc BbCc
Sperm
Eggs
H.H.Multiple Multiple Alleles:Alleles:
H.H.Multiple Multiple Alleles:Alleles:1.1. ABO Blood Groups:ABO Blood Groups: - 4 blood types: A, B, AB, O
- caused by a protein in the membranes of red
blood cells- 3 alleles for this protein:
IA, IB, i
- Genotypes for the 4 blood types:
Type A: IA IA, IAiType B: IB IB, IBiType AB: IA IB Universal Recipient
Type O: ii Universal Donor
2.Rh Blood Groups:2.Rh Blood Groups:- an example of multiple alleles- there are about 8 dominant alleles
(+)- one recessive allele (-)
III.III. Nondisjunction:Nondisjunction:III.III. Nondisjunction:Nondisjunction:- homologous chromosomes fail to
separate during meiosis
III.III. Nondisjunction:Nondisjunction:III.III. Nondisjunction:Nondisjunction:- Down Syndrome (Trisomy 21)- Klinefelter’s Syndrome (XXY)- XYY Syndrome- Turner’s Syndrome (Monosomy X)
(X)- Trisomy X (XXX)
Down Down syndromesyndrome
(Trisomy 21)(Trisomy 21)
Down Down syndromesyndrome
(Trisomy 21)(Trisomy 21)
Incidence of Down Syndrome
Incidence of Down Syndrome
10 20 30 40 500
100
200
300
400
Age of Mother (years)
Nu
mb
er
per
1000 B
irth
s
Turner’s Syndrome (Monosomy X)
Turner’s Syndrome (Monosomy X)
XYY SyndromeXYY Syndrome
Trisomy X (XXX)
Trisomy X (XXX)
Klinefelter’s Syndrome (XXY)
Klinefelter’s Syndrome (XXY)
Down Syndrome (Trisomy 21)
Down Syndrome (Trisomy 21)
Normal FemaleNormal Female
Edward’s Syndrome (Trisomy 18)
Edward’s Syndrome (Trisomy 18)
IV. Fetal Testing:IV. Fetal Testing:IV. Fetal Testing:IV. Fetal Testing:- Amniocentesis- Chorionic Villus Sampling- Ultrasound
AmniocentesisAmniocentesis
Ultrasound imageUltrasound image
Head
Body
Head
Body
Ultrasound Of FetusUltrasound Of Fetus
TheTheTheThe
EndEndEndEnd
Human Human ChromosomesChromosomes
(23 homologous (23 homologous pairs)pairs)
Human Human ChromosomesChromosomes
(23 homologous (23 homologous pairs)pairs)