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03-Heredity & Environment

03-Heredity & Environment. Genes. DNA (deoxyribonucleic acid) The basis of heredity Chromosome Molecule of DNA Make up chromosomes Humans = 46 (23 pairs) of chromosomes Genes = Section of chromosomes Allele = Slight normal variation in a gene. Genome = Code for making an individual.

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03-Heredity & Environment

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  1. 03-Heredity & Environment

  2. Genes • DNA (deoxyribonucleic acid) • The basis of heredity • Chromosome • Molecule of DNA • Make up chromosomes • Humans = 46 (23 pairs) of chromosomes • Genes = Section of chromosomes • Allele = Slight normal variation in a gene

  3. Genome = Code for making an individual • 20,000 genes (99% in other creatures also) • Genotype = The full set of genes for a specificorgasmorganism (entire genetic inheritance) • Phenotype • What you look like based on your genes • Appearance, personality, intelligence • Genotype = Hidden in your genes • Phenotype = Observable characteristics based on genes – E.g. brown eyes

  4. Beginning of life

  5. Gamete Sperm Ovum (egg) Each has23 chromosomes (one half of 46)

  6. Zygote Single cell from two gametes

  7. Male or female? 23rd pair of chromosomes Female = XX Male = XY

  8. Twins • Monozygotic (identical) twins • From one zygote • Share 100% genes • Dizygotic (fraternal) twins • Two sperm penetrating two ova • Share 50% of their genes

  9. ART = Assisted Reproduction Technology • IVF = In Vitro Fertilization • Sperm mixed with ova in glass dish • Viable embryos implanted • ICSI (Intracytoplasmic sperm injection) • Intrafallopian sperm injection

  10. One cell to many How genes interact Genotype = Entire set of genes (about 20,000) Phenotype = Appearance (blue eyes) and behavior (alcoholic)

  11. Genotype to phenotype • How genes affect appearance and behavior • Genes + Environment = Phenotype (Appearance & behavior) • E.g. Alcoholism • Genes(Varies in intensity) + Environment (Encourages or discourages drinking) = Result

  12. Epigenetic • All characteristics are determined by both genes and environment • E.g. height and nutrition

  13. Additive heredity • Some alleles (gene variations) combine to affect appearance and behavior

  14. Dominant – recessive heredity Dominate genes are more influential than recessive genes. E.g. Brown eyes (Mother-dominate) + Blue eyes (Father-recessive) = Brown eyed child Being a carrier for blue eyes can effect this

  15. Genetic (chromosomal) abnormalities • Most often related to age of mother • Extra chromosome • E.g. Down Syndrome = 47 chromosomes

  16. Abnormalities of the 23rd. Pair • Humans have 44 chromosomes + one X + an “X” or ”Y” • Embryos do not develop without one X • Missing chromosome • E.g. XO • Three sex chromosomes • XXY • XYY • Appear normal until puberty

  17. Genetic Counseling Find harmful conditions Affect insurance coverage Jeopardize the marriage

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