Cheat Sheet Quiz 1 - Co-dominance heterzygote shows...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Co-dominance: heterzygote shows phenotypes of both alleles fully/equal Incomplete dominance: two alleles of heterzygote interact resulting in intermediate phenotype Forward genetics —observed phenotype then look for causal genetic differences Begins with observed variation in phenotype Looking for patterns of inheritance in descendents of crosses b/t individuals w/different phenotypes Primary purpose: to find the normal pathway of metabolism and development by looking at mutants I) Mutations are individually mapped II) Making crosses b/t strains puts mutations in different combinations III) Characterize DNA of different variants (alleles) of genes and explain from variant DNA sequences the differences in structure, function, amounts, and localization within the organism of the metabolically active molecules Reverse Genetics : normal DNA create mutation analyze function of DNA sequence by observation of phenotypic changes. Advantage: large number of mutations of specific kinds can be made Southern Blot—probing for specific DNA Northern blot—probing for a specific RNA To determine if a gene is being transcribed in a tissue Western blot—probing for a specific protein Usually formed with antibodies Developmental noise --Random events in development that lead to variation in phenotype Mendel’s law of equal segregation --in meiosis, the members of a gene pair separate equally into eggs and sperm SINGLE GENE INHERITANCE 1:1 for Y/y x y/y 3:1 for Y/Y x Y/y 1:2:1 for Y/y x Y/y PHENOTYPIC RATIONS Monohybrid test-crossed: 1:1 Monohybrid selfed: 3:1 Dihybrid testcrossed (ind. Ass.): 1:1:1:1 Dihybrid selfed (ind. Ass): 9:3:3:1 Trihybrid test-crossed (ind.): 1:1:1:1:1:1:1:1 GENE INTERACTIONS 9:7 ratio—genes in same pathway Double mutant has same phenotypes as two single mutants Each mutant allele controls different step in same pathway Can also come from gene regulation o Regulatory gene produces protein that binds to regulatory stream upstream of target gene o Target gene would be transcribed at low levels Absence of either gene function leads to absence of end product of the pathway 9:3:4 ratio—recessive epistasis Double mutant shows phenotype of one mutation but not other o Epistatic—overriding mutation o Hypostatic—overridden mutation Results from genes in same pathway Epistatic mutation is in gene upstream of overridden one Can be developmentally downstream Typically 3 phenotypes segregate 12:3:1 ratio—dominant epistasis Suppressor—mutant allele that reverses effect of mutation of another gene, results in wild-type or near wild-type phenotype Gene products normally interact Sometimes have no effect in absence of other mutation or can produce own abnormal phenotype Screening Expose mutant to mutation-causing agents Screen for wild-type descendents o Most will by revertants (reversals of org. mutational event)
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern