PowerPoint PresentationSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 45Slide 46Slide 47Slide 48Slide 49Slide 50Slide 51Slide 52Slide 53Slide 54Slide 55Slide 56Slide 57Slide 58Slide 59Slide 60Slide 61Slide 62Slide 63BIO 325 – GeneticsVariation in Chromosome Structure and Number"Sir, if you were my husband, I would poison your drink." -- Lady Astor to Winston Churchill"Madam, if you were my wife, I would drink it." -- His replyVariation in Chromosome StructureChromosomes are named according to the location of their centromere. Variation in Chromosome Structure(b) A comparison of centromeric locationsThis slide illustrates various changes in chromosome structure. Variation in Chromosome StructureWhat do you see with regard to changes in the amount of genetic material within a chromosome and/or rearrangement of the genetic material within or between chromosomes?Variation in Chromosome StructureNote the different types of deletions. How do you think a deletion would typically affect an organism? What about where the deletion might occur?Variation in Chromosome StructureCri-du-chat (pronounced cree du shaw) syndrome in humans is caused by a deletion in the short arm of chromosome 5.Variation in Chromosome StructurePrader-Willi and Angelman syndromes are due to a deletion in chromosome 15. Variation in Chromosome StructurePrader-Willi SyndromeThe difference depends on whether the chromosome with the deletion is inherited from the mother or the father.AngelmanSyndromeDeleted regionWhat’s happening in this figure?Variation in Chromosome StructureWhat’s happening in this figure?How do you think duplications might affect an organism?Variation in Chromosome StructureAn example in humans is the neurological disorder Charcot-Marie-Tooth disease, which is caused by a small duplication in the short arm of chromosome 17. Variation in Chromosome StructureWhat does this figure show?Variation in Chromosome StructureWhat does this figure show?What’s a gene family?Variation in Chromosome StructureWhat can you tell me about genes that are derived from a single ancestral gene? Variation in Chromosome StructureWhat are paralogous genes? What are orthologous genes?Variation in Chromosome StructureThe globin gene family in humans would be an example of what? Comparable globin genes (e.g.,  globin) in humans and chimpanzees would be an example of what?Variation in Chromosome StructureVariation in Chromosome StructureNote the different types of inversions. What’s the deal with regard to the total amount of genetic material in the chromosome? What about phenotypic effects of inversions?Variation in Chromosome StructureWhat is an inversion heterozygote? Any problems with chromosome pairing during meiosis?Note the different types of translocations. What usually happens in translocations with regard to the amount of genetic material within a chromosome and the rearrangement of the genetic material between chromosomes? Variation in Chromosome StructureWhat is a Robertsonian translocation? What is an unbalanced translocation? What has happened with regard to translocation in familial Down syndrome? What is shown in this figure?Variation in Chromosome StructureVariation in Chromosome StructureThis is the type of chromosome pairing you might see during meiosis I in individuals with reciprocal translocations; it is called a translocation cross. Think this might cause some problems?Variation in Chromosome NumberVariation in Chromosome NumberWhat does this figure show?Why is aneuploidy usually detrimental to the phenotype of the individual?Variation in Chromosome NumberStatement: Approximately 5-10% of fertilized human eggs result in an embryo with an abnormal chromosome number, and almost 50% of spontaneous abortions are due to aneuploidy.Variation in Chromosome NumberYou should know the chromosomal situations that cause these. Don’t worry about the characteristics. Variation in Chromosome NumberDown Syndrome – Trisomy 21Klinefelter Syndrome – XXY MalesJacobs Syndrome – XYY MaleTrisomy X FemaleTurner Syndrome Female - XOWhat does this graph show?Variation in Chromosome NumberIn Down syndrome, the chromosomes do not separate correctly during anaphase (called nondisjunction). This may be due to the age of the primary oocyte, but other factors may also contribute.Variation in Chromosome NumberVariations in euploidy occur naturally in a few animal species.Variation in Chromosome NumberVariations in euploidy occur naturally in a few animal species. Most animals are diploid, and changes in the number of chromosome sets are not tolerated. Exceptions are: Variation in Chromosome NumberIn many species of bees, wasps and ants, one sex (usually males) is haploid and the other sex is diploid, a system known as haplodiploidy. Variation in Chromosome NumberSome vertebrate animals, such as amphibians and reptiles, are polyploid. Hyla chrysoscelisHyla versicolorVariation in Chromosome NumberVariations in euploidy are common in plants.Variation in Chromosome NumberVariations in euploidy are common in plants. Variation in Chromosome NumberWhat do you see here?Variation in Chromosome NumberWhat is chromosomal nondisjunction and what is the usually result? Variation in Chromosome NumberWhat is chromosomal nondisjunction and what is the usually result? What about meiotic nondisjunction?Variation in Chromosome NumberWhat is chromosomal nondisjunction and what is the usually result? What about meiotic nondisjunction?What about mitotic nondisjunction?Variation in Chromosome NumberWhat do you see happening as a result of nondisjunction during meiosis I?Variation in Chromosome NumberWhat do you see happening as a result of nondisjunction during meiosis II?Variation in Chromosome NumberMeiotic nondisjunction as illustrated in the previous two slides can produce aneuploidy. Variation in Chromosome NumberMeiotic nondisjunction as illustrated in the previous two slides can produce aneuploidy. What about complete nondisjunction of all the chromosomes?Variation in Chromosome NumberMeiotic nondisjunction as illustrated in the previous two slides can produce aneuploidy. Complete nondisjunction leads to sex cells that are