genetic inheritance

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Table of Contents Exit 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 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 Presentation

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Page 1: 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

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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)