BIOL 3333 1st Edition Lecture 22Departures from Diploidy in Plants- tolerances for aneuploidy and polyploidy contribute to speciation- can propagate from somatic tissue- increases in ploidy may lead to increases in plant size- tolerances for anueploidy and polyploidy may facilitate genetic manipulation- monoploids can be generated fem gametes and used in selection experiments - chromosome number can be doubled (colchicine treatment) restoring ability to propagate sexually Polyploidy in plants-polyploid species - number of complete chromosome sets - autopolyploids: contain multiples of the same chromosome set (same species)- allopolyploids: contain multiples of different chromosome sets (different species) - hybridizations b/w related species may lead to pairing problems during meiosis*triploids are often sterile due to pairing problems during meiosis*even numbers of chromosomes in polyploids may lead to more normal segregation and partitioning of chromosome sets*If paring partners can be provided for homologs in allopolyploids: sterility can be relieved The study of Mutation and Bacterial Genetics - no genetics w/ out variation - most of the phenotypic alterations we have discussed thus far may be classified as “point” mutations: single base pair change or alteration in a small number of bases Classification of Point Mutations- DNA level- Transition: purine to purine; pyrimidine to pyrimidine - Transversion: purine to pyrimidine; vise versa These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Classification of Mutations- Protein level- silent mutation: GGG GGC both glycine- synonymous mutation: AAA AGA both positively charged (basic)- missense mutation: CGC CCC (arg to pro - charged to neutral)- nonsense mutation: CAG UAG (amino acid signal to stop signal in protein synthesis)Mutant Types- Morphological mutations: affect outwardly visible properties- lethal mutations: loss of viability; change in characteristics ratio or number of recovered progeny- biochemical mutations: can lead to changes in the growth requirements of an organism- conditional mutations: - Particular environmental conditions may affect whether an allele exhibits a particular phenotype- Permissive conditions: the allele produces a functional gene product- Restrictive conditions: the allele produces a non-functional or sub-functional gene product*coat color in siamese cats - temperature sensitive mutation in melanin productionLoss of Function Alleles- loss of function; generally recessive, lead to decrease in amount of gene product- null alleles: no gene product produced- weak or “leaky” alleles: some gene product still being produced- haplosufficient vs haploinsufficient: - is one copy of a wild type allele capable of a wild type phenotype?Gain of Function Alleles- gain of function: can be dominant - a mutant phenotype can arise even in the presenceof a wild type allele- mutation may produce a new function or altered function- eg. receptor now capable of responding to extracellular signal without binding that