Download - Lifespan Chapter 2 A Online Stud
1
Chapter 2The Start of Life: Genetics and Prenatal
Development
© 2006 Pearson Education/Prentice-Hall Publishing
2
Heredity
3
Heredity
• The human genetic code is transferred by gametes.– Sperm– Ova
• The sex cells from the mother and father that form a new cell at conception (aka sperm and ovum).
4
Heredity
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Fertilization = sperm + ovum (the gametes) = one set of paired chromosomes = single new cell, a zygote.
5
• The 23rd chromosome determines the sex of the child.– Females are XX.
– Males are XY.
– The FATHER’s sperm determines the sex of the child.
6
• Monozygotic/DizygoticSome Terms to Remember
7
• Concordance rateSome Terms to Remember
8
Sandra Scarr: Genetics can influence environment in 3 ways:
1. Active (niche-picking) genotype-environment effects - children seek out environments they find compatible and stimulating
2. Passive genotype-environment effects - parents raise children in the way in which they are comfortable
3. Evocative genotype-environment effects - child’s characteristics elicit certain types of environments
9
• Dominant/Recessive [next]• Genotype – genetic material• Phenotype – observable• Gregor Mendel
Some Terms to Remember
10
b BB bb bB B
MotherB b
FatherB b
b
B
Blond hair
Brown hair
How Brown-Haired Parents Can Have a Blond-Haired Child
The gene for blond hair is recessive.
11
Some Genetic Disorders
Down Syndrome
Sickle-Cell Anemia
Tay-Sachs
Klinefelter’s Syndrome
12
Behavioral Genetics
• How behavioral disorders may have a genetic basis (e.g., schizophrenia).
• How genetic defects may be remedied.• The inheritance patterns of genetic
disorders.• How physically damaged genes
contribute to genetic disorders.• Gene therapy, genes to correct a
particular disease are injected into a patient’s bloodstream
• Germ-line gene therapy, genetic modifications can correct problems for unborn AND future generations
• Cloning
13
The Start of LifeAlternate forms of fertilization
(Reproductive Technology)
Artificial Insemination
14
The Start of LifeAlternate forms of fertilization
(Reproductive Technology)
In vitro fertilization (IVF)
Eggs are harvested from the woman’s ovaries, fertilized in the lab, and then deposited in the uterus
15
The Start of LifeAlternate forms of fertilization
(Reproductive Technology)
Gamete intrafallopian transfer
16
The Start of LifeAlternate forms of fertilization
(Reproductive Technology)
Zygote intrafallopian transfer(~ IVF + GIFT)
17
Success Rates of Three Different Assisted Reproduction Techniques
0
10
20
30
40
29.2%31%
24.5%
ZIFTIVF GIFT
There is little variation in success rates based on couples’ ages.
18
This single cell is transformed into a person by the human genetic code.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Zygote
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
19
The Start of Life The Onset of Development
Germinal Stage(first two weeks)
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Germinal disc 0.8 hours post fertilization
20
The Start of Life The Onset of Development
Embryonic Stage (two to eight weeks)
21
Gastrulation
• Ectoderm
• Endoderm
• Mesoderm
22
The Start of Life The Onset of Development
Fetal Stage (eight weeks until birth)
During the fetal period, the proportions of the body change dramatically.
23
Prenatal Testing
Chorionic Villus Sampling (CVS)
Amniocentesis-- Often goes along with genetic counseling
Ultrasound Sonography
24
Threats to Prenatal Development
• Illnesses• AIDS• Aspirin• Thalidomide• Marijuana• Cocaine• Cigarettes• Alcohol