quiz 3 Flashcards
(21 cards)
aneuploidy
monosomy: loss of a single chromosome from diploid genome
euploidy
complete haploid sets of chromosomes are present
polyploidy
more than two sets of chromosomes are present
autopolyploidy
addition of one or more sets of chromosomes identical to the haploid complement of same species
allopolyploidy
combination of chromosome sets from different species as a consequence of hybridization
how does autopolyploidy arise
diploid gamete is produce- failure of chromosomes to segregate during meiotic division
two sperm fertilize one ovum- triploid zygote
how does allopolyploidy arise
hybrid may be sterile - cannot produce viable gametes
chromosomes are not homologous- cannot synape in meiosis
how does nondisjunction happen?
chromosomes fail to separate in meiosis or mitosis
haploinsuffieniency
single copy of gene is insufficient to provide life-sustaining function for organism
how can trisomies happen
extra chromosomes produces more viable organisms than loss of chromosome if its small
forward genetics
finding the genetic basis for a particular phenotype
reverse genetics
understanding the phenotype associated with a gene
examples of how to do reverse genetics
gene silencing
targeted mutagenesis
RNAi
CRISPR
crossing over
occurs between two nonsister chromatids
both parental and reombinant gametes are produced
complete linkage
no crossing over between two genes
produces parental gametes
linkage groups
corresponds to haploid number of chromosomes
chiasmata
synapsed chromosomes in meiosis wrap around each other
X-shaped intersections with points of overlap
single crossovers
relative distance between two loci influences amount of recombination and crossing over
double crossover
results from double exchanges of genetic material
What happens if two genes are more than 50 cMs from each other?
It is difficult to determine if they are on the same gene
