1. Genetic Inheritance Conception
The union of sperm and ovum create a zygote
The zygote contains a complete set of 46 chromosomes
The first 22 pairs are called autosomes.
The 23rd pair are the sex chromosomes.
DNA
Genes

2. Genetic Principles Genes Genotype. Phenotype Reaction range Alleles
Homozygous Alleles (similar)
Heterozygous Alleles (different)
dominant - recessive gene principle
incomplete dominance (blending)
codominance (type AB blood)

3. Genetic Inheritance Single Gene-Pair Inheritance
Polygenetic Inheritance
Genetic Imprinting
Genes are (chemically marked) in one of the parents and have different effects depending on which parent carries it.
Huntington disease manifests earlier if passed on by the male
Asthma / females , Diabetes / males

4. Genetic Inheritance Sex Linked Genes or Traits (X-linked inheritance)
ex: hemophilia, red/green color blindness
Mutations
A sudden, permanent alteration in DNA
occurs spontaneously or by environmental hazards
Chromosomal Abnormalities
Often the result of the 46 chromosomes not being divided equally (too many or too few)
Down Syndrome

5. Genetics & Environment
Heritability:
The amount of variability in a population on some trait dimension that is attributable to genetic differences among those individuals

6. Gene-Environment Relationships
Epigenetic View: Heredity  Environment
Passive Gene-Environment Relation
Evocative Gene-Environment Relation
Active Gene-Environment Relation
Shared and Non-shared Experiences

7. Stages of Prenatal
Development

8. Germinal Stage (Weeks 1-2)
The zygote, begins to divide, and travels down the fallopian tube.
The new cells form the blastocyst, which attaches itself to the uterine wall
The blastocyst forms several layers of cells
The outer cells (trophoblast) form the placenta.

9. Embryonic Stage (weeks 3 – 8)
The inner cells of the blastocyst which will become the embryo differentiate into three layers:
Ectoderm: Outermost layer which will become skin, hair, nails, the nervous system, and sensory receptors
Mesoderm: Middle layer which will develop into the circulatory system, bones, muscles, excretory and reproductive system
Endoderm: Undermost layer which will develop into the digestive and respiratory systems

10. Embryonic Stage (weeks 3 – 8)
The formation of organs begins (organogenesis)
Sexual differentiation takes place around the 7th or 8th week
By the end of the embryonic stage about 95% of body parts and systems have begun development.

11. Fetal Stage (Week 9-Birth)
This period involves the dramatic increase in body size and completion of all physical structures
Age of viability = approx. week 25

12. Prenatal Growth Occurs in three patterns: Orthogenic
Cells are all the same and then differentiate
Cephalocaudal:
Latin for “from head to tail”.
Proximodistal:
Latin for “from near to far”.

13. Influences on Prenatal Development
Nutrition
Stress
Mother’s Emotional state
Mother’s Age
Nearly 50% of pregnancies among women in their 40’s and 50’s result in miscarriage.
Father

14. Influences on Prenatal Development
Teratogans are any disease, drugs, or other environmental agents that can cause damage to a developing fetus.
Effects depend on:
Dose
Heredity
Presence of other teratogens
Age of child
Sensitive period

15. Postnatal (Postpartum) Depression
Occurs in 1/10 new mothers
Effects bonding and initial care of child
Effects on mother
May not want child
Mood lability and other symptoms of depression
Psychosis
SI / HI

16. Postnatal (Postpartum) Depression
Effects on child
Susceptibility
Past episode(s) of post partum (30 to 50% chance with each subsequent delivery)
Personal past history of a mood disorder
Family history of Bipolar disorder (even if not personally experienced)