BIO 305 1st EditionExam 2 Study Guide: Lectures 8-14Lecture 8Know the three types of Non-Mendelian Inheritance (cytoplasmic inheritance, maternal effect, and imprinting) and how these affect the ratio of phenotypes of progeny. Understand the nature of mitochondrial DNA and the cause and effect of mtDNA mutations.General Features of Uniparental Inheritance: Cytoplasmic Inheritance1) No segregation via meiosis- Ratios typical of Mendelian segregation do not occur- No recombination2) Reciprocal crosses show that zygotes receive cytoplasm from the mother3) Parental leakage occurs at low levels and is transientUnderstand how variegated four-o’ clock plant phenotypes ariseUnderstand why the progeny of green algae all show either resistance or sensitivity Understand why phenotypes that are cytoplasmically inherited tend to be related to energy productionDifferences between Chloroplast and Mitochondrion Genome Mitochondrion are smaller and have less genes, contain non-capped mRNAs, no Shine-Delgarno sequence, and the genes involved are involved in oxidative phosphorylation instead of photosynthesisBoth are circular, encode rRNA and tRNA, and are maternally inheritedMitochondrial DNA What aspects of mitochondrial DNA make it useful for forensics? Maternity analysis? Conservation genetics? Phylogenetic analysis?Define homoplasmy vs. heteroplasmyDescribe segregational, neutral, and suppressive mutations affecting mitochondrial function:1) Segregational – nuclear mutation and Mendelian inheritance (50/50 neutral, petite)2) Neutral – lacks most mtDNA and cytoplasmic Inheritance (100 neutral)3) Suppressive – mutant mtDNA acts dominant and cytoplasmic inheritance (depends)Describe sensitivity of tissue to mitochondrial mutation:central nervous system  skeletal muscle  heart muscle  kidney  liverPedigrees: If a pedigree shows very sporadic affected individuals, it is likely to be due to mutant mtDNA. This is because a certain percentage of mutant mitochondrion must be met before the phenotype is expressed.Maternal Effect: Phenotype is determined by the maternal genotype NOT the progeny’s genotype or the maternal phenotype (Snail coiling)This is because of either proteins, mRNA, etc. (maternal factors) that are deposited in theoocyte before fertilizationFor maternal effect, just remember that the phenotype of the progeny purely depends on the genotype of the mother, so write out the genotypes separately from phenotypeLecture 9Changes in Chromosome NumberUnderstanding the difference between Aneuploidy and Euploidy:be able to identify as either monosomy, trisomy, triploidy, diploidy, etc.How does monosomy affect humans? Trisomy? What about for plants?Why are odd-numbered Polyploids less common in nature than even-numbered?Understand autopolyploidy vs. allopolyploidy vs. endopolyploidy(think multiplication vs. fusion vs. endomitosis)What are the three ways autopolyploidy can occur?What is an amphidiploid and why are they usually fertile?How do you explain aneuploidy with non-disjunction? Chromosomal pairing during meiosis of an aneuploid?Colchicine – induces formation of polyploids by interfering with spindle formation in mitosisExplain this process at each stage at the chromosomal level. What are the effects?Changes in Chromosome NumberUnderstand the five types of chromosomal alteration:Deletion, Duplication, Inversion, TranslocationWhat are the three types of deletionWhen a phenotype mysteriously ‘disappears” when all parents are true-breeding dominants: deletion can lead to pseudodominance What are the three rules of duplication? What causes it?Inversions require two breaks and a loop in the chromosomeWhat is the difference between paracentric inversion and pericentric inversion?Why are inversions an issue for mostly heterozygotes? What is crossover suppression?Results of paracentric heterozygote inversions  dicentric and acentric chromosomesResults of pericentric heterozygote inversions  duplications and deletionDoes crossover occur in looped regions? What is implied for genes within inversions?Why is reduced recombination important in the evolutions of the some organisms but not others?Lecture 10Understand the four types of translocations: intrachromosomal translocation, interchromosomal translocation, reciprocal translocation, robertsonian translocationMeiosis is a problem in heterozygotes:Homologues create a cruciform arrangement in metaphase – error results when there is a deficiency in the blue part and extra orange or when there is extra orange and blue deficiencyWhat are the 3 key features of inheritance of Fragile X Syndrome?Define: AnticipationIn a pedigree, ancestor males and females may be half-shaded to indicate that they carry premutations and the descendant sons will very frequently be full-shaded as a result (aka they carry the Fragile X disease)What is the molecular explanation for this?Lecture 11What are traits that can be quantified? Explain Edward East’s experiment, what did he find?Define: Polygenic Inheritance, What is responsible for continuous variation?To predict ratios of different phenotypes for a true-breeding cross with additive alleles, you can use a forked line diagram on the F2 generation.Ex: bell curve in frequency of alleles for F2:1:4:6:4:1 for a Mendelian co-dominant crossNumber of phenotypes that can result from additive genes: 2N+1Proportion of F2 individuals expressing either extreme phenotype = 1 4^nKnow how to find the six parameters of a normal curve and understand how they relate:Mean, Variance, Standard Deviation, Standard Error, Covariance, Correlation CoefficientHeritability – how much genes affect phenotype in a given population under certain conditions Broad-sense heritability – The degree to which a trait is genetically determined, expressed as a ratio of total genetic variance to phenotypic variance Narrow-sense heritability – The degree to which a trait passed from parent to offspring, expressed as the ratio of additive genotypic variance to phenotypic variance, it is also the slope of resemblance of quantitative phenotype offspring in relation to parent and response – selection differentialLecture 12QTL – DNA containing or linked to the genes that underlie a quantitative traitSNPS – molecular markers used to map regions of genes for a quantitative traitQTL Mapping using LOD score as Y-variable per chromosome: gene for quantitative trait is indicated when it strongly crosses a threshold