Final Flashcards
coefficient of relatedness
the percent of shared genes that two individuals have. This number is between 0 and 1. It can be found by taking 1/the number of marriages the two individuals are separated by times 2. (ex. Mother and child: 1/2)
telocentric
when a chromosome’s centromere is located at the terminal end of the chromosome
acrocentric
when a chromosome’s centromere is located toward one end of the chromosome
metacentric
when a chromosome is x-shaped. The centromere is located about equally from each telomere.
dicentric
when an abnormal chromosome contains two centromeres. This is the result of two chromosome pieces attaching together
paracentric
an inversion that twists the chromosome without involving the centromere. “away from the center”
polyploidy
an organism having more than two paired sets of chromosomes
tetrasomic
four copies, instead of two, of a chromosome
triploid
having three copies of each chromosome, instead of the normal two
haploid
having a single set of unpaired chromosomes
trisomy
three instances of a particular chromosome, instead of the normal two (ex. trisomy 21= down syndrome)
tetraploid
having four copies of having chromosome
meiosis
cell division that results in four daughter cells having half the number of chromosomes that the parent did. Each genetically different from the parent
genomic imprinting
the expression of one gene depends on whether it was inherited by the mother or father. Genes might be turned off if they were inherited by one or the other.
reciprocal translocation
two nonhomologous chromosomes exchange parts
epistasis
one gene controls the expression of a second gene
transversion point mutation
a two ring purine is replaced with a single ring pyrimidine
missense mutation
a type of nonsynonymous point mutation. A single base change changes the amino acid used.
telomerase
an enzyme that adds nucleotides to telomeres, especially in cancer cells
nonsense mutation
a point mutation that causes a stop codon to appear where it shouldn’t
mutation
a change in a DNA sequence
polymorphism
a genetic change that is present in more than 1% of a population
“loss-of-function” mutation
recessive
“gain-of-function” mutation
dominant
germline mutations
originate in meiosis, affect all cells of an organism
somatic mutations
originate in mitosis, affect only cells that descend from changed cell
mitosis
replication of somatic cells
mutagen
agent that causes a mutation
de novo mutation
spontaneous, new, not caused by exposure to a known mutagen, slight chemical instability, alternating forms called tautomers
mutation rate in autosomal dominant genes
number of new cases/2x, where x is the number of individuals examined
carcinogens
mutagens that cause cancer
alkylating agents
replace a base (mismatch)
acridine dyes
add or remove bases
radiation
breaks chromosomes
uv radiation
creates thymine dimers
Ames Test
in vitro test, tests the mutagenicity of a substance
transition mutation
purine replaces purine, pyrimidine replaces pyrimidine
transversion
purine replaces pyrimidine or pyrimidine replaces purine
splice site mutations
alters a site where an intron is normally removed from mRNA, affects phenotype if intron is translated or exon is skipped
frameshift mutation
nucleotide changes not in multiples of three, shifts the frame and therefore amino acids
pseudogenes
a dna sequence similar to a gene but which is not translated, may not be transcribed into RNA, crossing over between pseudogene and functional gene can disrupt expression
anticipation
each generation has a more severe phenotype with a triplet repeat (adding Amino acids in groups of 3)
