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Heredity

Heredity. An introduction. YOUR Traits…. YOUR Traits…. YOUR Traits…. YOUR Traits…. YOUR Traits…. YOUR Traits…. YOUR Traits…. YOUR Traits…. YOUR Traits…. YOUR Traits…. Less desirable traits…. Polydactyly (6+ fingers/toes; autosomal dominant),

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Heredity

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  1. Heredity An introduction

  2. YOUR Traits…

  3. YOUR Traits…

  4. YOUR Traits…

  5. YOUR Traits…

  6. YOUR Traits…

  7. YOUR Traits…

  8. YOUR Traits…

  9. YOUR Traits…

  10. YOUR Traits…

  11. YOUR Traits…

  12. Less desirable traits… • Polydactyly (6+ fingers/toes; autosomal dominant), • Marfan syndrome (connective tissue disorder; an autosomal dominant disorder that has been linked to the FBN1 gene on chromosome 15) • Tay-Sachs disease (TSD, fatal in its most common variant known as Infantile Tay-Sachs disease; fatty acid deposits in brain nerve cells; autosomal recessive.) • Huntington's disease (autosomal dominant neurological disorder, cell death in brain 8/100,000)

  13. Polydactyly

  14. Marfan Syndrome

  15. Less desirable traits • Neurofibromatosis (autosomal dominant; causes tumors to grow along types of nerves, can affect the dev. of non-nervous tissues such as bones and skin. Type I, chrom. 17, (1/3000); Type II, chrom. 22, (1/40,000) • Hypertrophic cardiomyopathy (HCM, disease of the myocardium (the muscle of the heart) a portion of the myocardium is hypertrophied (thickened) without any obvious cause; most famous as a leading cause of sudden cardiac death in young athletes; a cause of sudden unexpected cardiac death in any age group and as a cause of disabling cardiac symptoms.)

  16. Neurofibromatosis

  17. Neurofibromatosis

  18. Neurofibromatosis • Joseph Merrick “The Elephant Man”

  19. History • Hippocrates • Ancient Greece (400 B.C.) • Pangenesis • particles from throughout body are passed to sperm or egg; also, changes in the body are passed on • Problem with it: • 1) Particles from somatic cells don’t make up gametes • 2) Changes in somatic cells (body) don’t affect gametes

  20. History • Blending Hypothesis • Early 19th century • Hereditary materials from m/f blend, or mix. • Problem with it: • “Mixing” isn’t true, original traits can show up again later.

  21. History • Gregor Mendel (1866) • Monk, lived & worked in an abbey in Brunn, Austria. Had attended U. of Vienna; knew physics, mathematics, chemistry. Worked in garden. • Studied peas. Curious as to why certain traits kept appearing on peas.

  22. History • Concluded these things: • 1. Inheritance controlled by “factors” passed from parents to offspring. • 2. Principle of Dominance/Recessiveness • 3. Law of Segregation • Pair of factors is separated during gamete formation (anaphase) • 4. Law of Independent Assortment • Factors separate independently during gamete formation(metaphase)

  23. Terms: • P generation: parents • F1 generation: offsp. of P’s • F2 generation: offsp. of F1 gen.

  24. Terms: • Hybrid (Cross): offsp. of two diff.varieties • Monohybrid Cross: Crossing one trait • Dihybrid: two traits Tri… • Allele: alt. forms of same gene • Homozygous: identical alleles for same char. • Heterozygous: 2+ diff. alleles for same char.

  25. An example:

  26. Terms: Phenotype: the expressed traits of an org: (what it looks like)

  27. Terms • Genotype (the genetic makeup of an org.)

  28. This is how Mendelcontrolled his crossesto produce a new generation…

  29. The F1 generations were all heterozygous for the trait being observed. The original P generations were pure homozygousfor the traits. Ex: The P gen. for flower color was PP x pp. The F1 was Pp x Pp.

  30. Terms: Consider the genotypes TT Tt tt • Dominant allele (in Heterotroph., allele that determines phenotype [T]) • Recessive allele (in Het., allele that has no noticeable affect on phen. [t])

  31. Terms: • Punnett Square • Tool used to predict offspring ratiosTry this: Show why there are about ½ males and ½ females born to humans…

  32. An example

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