more genetics Flashcards
point & frameshift mutation
substitution; insertion; deletion
insertion & deletion mutations can result in a frameshift, significantly affecting protein synthesis as mRNA sequences are read in sets of 3 (codons)
non-disjunction mutation
chromosomes fail to separate correctly during anaphase of meiosis
mutagens
mutagens damage DNA by changing its structure or breaking its bonds, leading to mutation
∴ DNA cannot be or is incorrectly read, affecting protein synthesis & leading to apoptosis or cancer
aneuploidy
non-disjunction results in daughter cells that contain an incorrect number of chromosomes
monosomy
aneuploidy where individuals only have one copy of a particular chromosome (2n - 1)
e.g. Turner Syndrome (monosomy X)
trisomy
aneuploidy where individuals have three copies of a particular chromosome (2n + 1)
e.g. Down Syndrome (Trisomy 21)
how do hereditary/inherited mutations affect the genotype of the offspring ?
germline mutations (occurs during meiosis) create new alleles
if the mutated gene (within sperm or egg) is fertilized into a zygote, the offspring’s genotype is affected
recombinant DNA
restriction enzymes cut DNA at recognition sites to isolate genes; sticky ends (used) & blunt ends (unused) are produced
the same restriction enzyme cuts a plasmid vector (bacteria) where the gene is inserted
DNA ligase joins the sticky end & the plasmid vector together
recombinant plasmid is inserted into bacteria to amplify (bacterial transformation)
polymerase chain reaction
utilizes polymerase enzymes to catalyze & amplify copies of a DNA sequence
3 steps : denaturation (split DNA), annealing (primers attach), elongation (polymerase builds)
generates a unique DNA profile
gel electrophoresis
DNA (negatively charged) is cut by restriction enzymes & separated by size via an electrical gel field (smaller the DNA fragment, greater the distance migrated towards the positive terminal)
analyzes a unique DNA profile
DNA profiling
determining DNA profiles through highly variable short tandem repeats (found in introns)
identifying unique genetic information can help : compare DNA samples to solve crimes; determine paternity
DNA sequencing
determining the specific order of nucleotides within a segment of DNA
mapping an species’ genome can help : identify the causes of disease & determine the possibility for gene therapy; classify organisms & provide insight into evolutionary relationships
co-dominance
both alleles are expressed in heterozygotes with a patched effect
e.g. white x red → white/red
R or R’
incomplete dominance
both alleles are expressed in heterozygotes with a blended effect
e.g. white x red → pink
R or R’
sex-linked alleles
genes carried on the X or Y chromosome
Xᴺ or Xⁿ
