genetic inheritance
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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. Genetic Principles . Genes Genotype. Phenotype - PowerPoint PPT PresentationTRANSCRIPT
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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
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Genetic Principles
Genes Genotype. Phenotype
Reaction rangeAlleles Homozygous Alleles (similar) Heterozygous Alleles (different)
dominant - recessive gene principle incomplete dominance (blending) codominance (type AB blood)
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Genetic Inheritance
Single Gene-Pair InheritancePolygenetic InheritanceGenetic 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
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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
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Genetics & Environment
Heritability:The amount of variability in a population on some trait dimension that is attributable to genetic differences among those individuals
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Gene-Environment Relationships
Epigenetic View: Heredity Environment Passive Gene-Environment Relation Evocative Gene-Environment Relation Active Gene-Environment Relation Shared and Non-shared Experiences
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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.
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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
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Embryonic Stage (weeks 3 – 8)The formation of organs begins (organogenesis)Sexual differentiation takes place around the 7th or 8th weekBy the end of the embryonic stage about 95% of body parts and systems have begun development.
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Fetal Stage (Week 9-Birth)
This period involves the dramatic increase in body size and completion of all physical
structuresAge of viability = approx. week 25
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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”.
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Influences on Prenatal Development
NutritionStressMother’s Emotional stateMother’s Age Nearly 50% of pregnancies among women in their 40’s and 50’s
result in miscarriage.Father
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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
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Postnatal (Postpartum) Depression
Occurs in 1/10 new mothersEffects bonding and initial care of childEffects on mother May not want child Mood lability and other symptoms of depression Psychosis SI / HI
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Postnatal (Postpartum) Depression
Effects on childSusceptibility 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)