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Genetics are awesomeeee.

Genetics are awesomeeee. Real ?. Name ?. Structure of DNA. Each DNA molecule is made up of two very long polymers D ouble helix: is the shape Nucleotides: are the building blocks: each has deoxyribose ( a 5 carbon sugar) phosphate group nitrogenous base . DNA double helix.

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Genetics are awesomeeee.

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  1. Genetics are awesomeeee. Real ? Name ?

  2. Structure of DNA • Each DNA molecule is made up of two very long polymers • Double helix: is the shape • Nucleotides: are the building blocks: each has • deoxyribose ( a 5 carbon sugar) • phosphate group • nitrogenous base

  3. DNA double helix

  4. Nitrogenous bases • There are four different nitrogenous bases thymine (T), cytosine (C), adenine (A), and guanine (G) • These four bases are the foundation of the genetic code. • These chemicals act as the cell's memory, instructing it on how to synthesize enzymes and other proteins. These four nucleotides encode everything an organism needs to live and protects this information with incredible accuracy.

  5. In a human being • DNA is broken down onto 46 separate chromosomes • Each chromosome has about 160 million nucleotide pairs • This massive amount of information is stored and replicated almost flawlessly!

  6. DNA Replication • INTERPHASE: Before a cell divides, its DNA is replicated • Semi Conservative replication: Two strands of a DNA molecule are separated, each ONE can be used as a template to produce a complementary strand.  • Each template and its new complement together then form a new DNA double helix, identical to the original.

  7. Before replication can occur, the length of the DNA double helix about to be copied must be unwound. INTERPHASE • The two strands must be separated, much like the two sides of a zippper: helicase • The enzyme DNA polymerase then moves along the exposed DNA strand, joining newly arrived nucleotides into a new DNA strand that is  complementary to the template.  

  8. Mitosis • 1 diploid cell to 2 diploid daughter cells • Interphase: G1 G2 and S G1 primary checkpt • Kinetochore of centromere • Amimal: cleavage furrow • Plant: cell plate • Prokaryotes: binary fission

  9. CDK’s • The Cell Cycle regulated by: cyclin-dependent kinases is regulated by binding to cyclins, • Cyclins: levels vary during the cell cycle. • Levels of CDK-molecules(kinases) are constant during the cell cycle, their activities vary because of the regulatory function of the cyclins.

  10. CDK’s • Cellreplication of genetic material, followed by: • a) Binary fission in prokaryotes and plastids (mitochondria , chloroplasts). In binary fission: asexual reproduction, a cell divides into two daughter cells after replication. • b) Budding (yeast, spores, Hydra) asexual reproduction in which a new organism buds from a cell protuberance: unequal fission. • c) Mitotic division of somatic cells • c) Meiotic division of germ cells (sexual reproduction)

  11. Cell Cycle Controls • Anchorage dependent: will only grow when anchored to some tissue (or inside a culture) • Density Dependent inhibition: stop growing when crowded.

  12. Meiosis I • STEP ONE MEIOSIS I: This is basically like the PMATI of a regular mitosis. Homologous chromosomes split • Meiosis is different because crossing-over. Prophase I • crossing over: an exchange of genes from 1 homologous chromosome to the other (genes from the chromosome you got from mom go onto the chromosome you got from dad. • This is why your children will not look exactly like their Nana or Grandpa….

  13. Recombinant phenotype • Linkage maps • Recombination: • Unlinked genes: independent assortment of chromosomes • Linked genes: crossing over • Recombinant phenotype: • Mom: brown hair and brown eyes • Dad: Blond hair and blue eyes • Baby: Brown hair and blue eyes

  14. Meiosis II • STEP TWO MEIOSIS II: • In Metaphase II all of the chromosomes line up along the center of the cell • Anaphase II shows the Sister Chromatidssplit • Each daughter cell will get one-half of the DNA • The cell membrane begins to pinch. When it's all over, you are left with four haploid cells that are called gametes.

  15. Mendel’s First Law • Mendel's First Law is the law of "Segregation” • Humans are Diploid. This means you get two alleles for each trait. • Segregation: you can only get ONE allele from mom. Only ONE from dad. • Mom has 2 alleles…. Which one she passes to you (her egg) is random. • In eye color B Brown is dominant. Blue (b) is recessive. • If mom has Brown eyes she could be BB or Bb. She can only pass ONE allele on in her egg. She passes Either B or b • Basis for Punnett Squares

  16. Segregation • - If mom had the genotype AaBb she would make four kinds of gametes(eggs): they would contain the combinations of either AB, Ab, aB or ab. • A is dominant (big feet): a is recessive (little ft) • B is dominant (black hair):b is recessive(blond) • So, mom would pass on either: • Big feet & black hair (AB), • big feet and blonde hair (Ab) • Little feet and black hair (aB) • Little feet and blonde hair (ab)

  17. Punnett Square • A punnett square is used to predict an expected outcome of a particular cross or breeding experiment. True breeding Test cross

  18. Independent assortment • Mendel's Second Law is the law of "Independent Assortment". • Homologous chromosomes line up randomly Not all blues to the left and red to the right • Offspring does not get all chromosomes from maternal nana or grandpa from mom

  19. Independent Assortment

  20. Genetic variation contributes to Evolution • Mutations create different versions of genes • Mechanisms for variation in Sexual: • Independent Segregation of alleles • Independent assortment of chromosomes • Crossing over (prophase I) • Random fertilization

  21. Non Mendelian Genetics • Some traits are not passed on the way the traits Mendel studied were. • Incomplete dominance • Co dominance • Multiple alleles • Epistasis: gene at one site effected by gene at another • Pleiotropy: gene with multiple phenotypic effects • Polygenic inheritance: mult. Genes involved: usually phenotype is on a scale: height, skin pigmentation

  22. Incomplete Dominance • Incomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not completely dominant over the other allele. This results in a combined phenotype.

  23. Codominance • A condition in which both alleles of a gene pair in a heterozygote are fully expressed, with neither one being dominant or recessive to the other.

  24. Multiple Alleles • Any set of three or more alleles or alternative states of a gene. • Only two of which can be present in an organism at a time. • Responsible for differences in expressions of a given trait. Example: brown eyes v. green eyes.

  25. Pleiotropy • Most genes have multiple phenotypic effects. The ability of a gene to affect an organism in many ways is called pleiotropy.

  26. Epistasis • Epistasis occurs when a gene at one locus alters or influences the expression of a gene at a second loci. In this example, C is for color and the dominate allele must be present for pigment (color) to be expressed.

  27. Polygenetic Inheritance • Qualitative variation usually indicates polygenic inheritance. This occurs when there is an additive effect from two or more genes. Pigmentation in humans is controlled by at least three (3) separately inherited genes.

  28. DiseasesPoint mutation • Point mutation: effect 1 gene • Substitution: change 1 base pair: may still get same amino acid, or 1 different amino acid • Addition/deletion: change whole chain thereafter

  29. Diseases caused by Point Mutation • Cystic Fibrosis: • Mutation in gene involved in movement of water and stuff in and out of cell • This causes the build up of thick, sticky mucus • Sickle Cell Anemia • Colorblind: • Genetic disease- (X-link): loss of cones in retina • Tay Sachs disease: • Genetic Disease – inherited- caused by mutation in gene to break down fatty substance…. Get lethal accumulation of fatty subst. in brain and spinal cord

  30. DiseasesGenetic (dominant/recessive) Dominant Recessive Cystic Fibrosis Tay Sachs Sickle cell anemia phenylketenuria • Huntingtons • Nuerofibromatosis • Marfan

  31. Sex linked disorders (recessive) Red green color blindness- malfunction in light sensitive cells in the eye Hemophilia- lack one or more proteins needed for blood clotting Duchenne muscular dystrophy- progressive weakening of muscles and loss of coordination

  32. Sex linked recessive

  33. Common Chromosomal Abnormalities http://anthro.palomar.edu/abnormal/abnormal_4.htm • Two Main Categories • Structural modification • Irregular number • Typically result from nondisjunction during meiosis • Polyploidy-complete multiples of sets of chromosomes (23+23+23) • Aneulploidy-addition or loss of chromosomes within a set (23+22)

  34. Autosomal Defects Down’s Syndrome • Typically trisomy of chromosome 21 • Some have translocation of 21 to 14 or 15 • 75-80% of Down syndrome children are born to women under 35 Monosomy • Only one set of chromosomes remains after fertilization • All fetuses will spontaneously abort http://anthro.palomar.edu/abnormal/abnormal_4.htm

  35. Male Abnormalities Sex Chromosome Abnormalities Female Abnormalities Metafemale(XXX) Unusually tall, low to normal intelligence Normal sex characteristics, fertile Turner Syndrome (XO) Ovaries do not develop, and do not ovulate Lack secondary sex characteristics Slight mental retardation Klinefelter Syndrome (XXY) High-pitched voice Asexual to feminine body type Low testosterone, sterile 1 in 500 XYY Syndrome Unusually tall, severe acne High testosterone levels, possibly leading to violence http://anthro.palomar.edu/abnormal/abnormal_4.htm

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