Genetics Flashcards
Assumptions of HW equil
- no mutation, no natural selection
- birth rate = death rate
- random mating
- no migration/gene flow
- large population
HW eqn and its derivative
p + q = 1
p^2 + 2pq + q^2 = 1
Autosomal vs Sex linked. Barr bodies
assoc w/ non-sex chm’s vs associated with sex chm’s (X chm; assume sex-linked = recessive unless told otherwise). When one of the X chrms in females = inactivated to prevent redundancy in gene products (ie. mRNA and proteins)
Can RNA polymerase proofread?
No
Is the DNA strand more similar to mRNA or tRNA?
tRNA
silent vs missense vs nonsense mutation
point mutation occurs but no conseq vs one aa substitutes for another aa in final peptide vs leads to premature stop codon —> shorter peptide length
Mendel’s 1st law of segregation vs 2nd law of segregation
genes exist in alternative forms (ie. alleles), organism has 2 alleles of each gene (1 from each parent), 2 alleles segregrate during meiosis –> each gamete has 1 allele, if organism has 2 diff alleles –> 1 = expressed and 1 = silent vs inheritance of 1 gene doesn’t affect inheritance of another gene
Penetrance vs expressivity (constant vs variable)
proportion of pop w/ given genotype that actually shows corresponding phenotype at all; if a problem gives penetrance, make sure to include it in calculations by multiplying its %age vs diff manifestations of same genotype in pop (same genotype –> same phenotype vs same genotype –> diff phenotype)
What are transposons?
Elements that can insert/remove itself from genome
Diff b/w deoxy/ribose
no O at C2 for deoxy
Chromosomal mutations: translocation vs inversion
DNA segments = switched b/w chrms vs DNA segment = reverse
Chargaff’s rules
%A = %T, %C = %G; A + G = C + T (purines = pyrimidines, they equal 50 on each side)
Difference between wild type and mutant strains?
Mutants don’t have the gene at all but wild type do
Leakage
Transfer of genes from one organism to another
Advantageous vs deleterious mutations. Inborn errors of metabolism
mutations but results in an advantage (ex: sickle cell gives less likely chance to die from malaria) vs mutations w/ detrimental results (ex: xeroderma pigmentosum aka XP = genetic defect in nucleotide excision repair mechanism –> can’t repair damaged DNA). Subclass of deleterious mutations, defect in genes required for metabolism (ex: in phenylketonuria aka PKU, phenylalanine hydrolase can’t metabolize phenylalanine like it should)
