15 - THE MOLECULAR BASIS OF INHERITANCE Flashcards
Large Scale Chromosomal Changes
what is ploidy
the number of “sets of chromosomes” in an organism
what is euploidy
complete extra set of chromosomes
what is aneuploidy
extra chromosomes but it is not an extra set
in which organisms does polyploidy occur
common in plants
uncommon in animals, they usually do not survive
what is autopolyploidy
the extra sets are from the same species
what are the consequences of autopolyploidy in animals and in plants
lethal in animals
for plants it results in an increase in size
these are somatic consequences of polyploidy
what are the germline consequences of polyploidy
gametes are not viable
the individual is sterile
chromosome segregation in mitosis
chromosome segregation in meiosis
how does meiosis happen in diploids
how does meiosis 1 happen in triploids
how does meiosis 2 happen in triploids
how can we also get to 1n and 2n gametes from a triploid organism
then when they separate in meiosis 2:
from the one on the left you get 2 1n gametes
from the one on the right you get 2 2n gametes
how can normal euploid gametes be generated in a triploid
if all the extra chromosomes segregate BY CHANCE to the same daughter cell
how does meiosis happen in tetraploid
chromosomes can pair since there is an even number, which helps in proper segregation
meiosis from a tetraploid cell will generate 4 euploid 2n gametes
what causes autopolyploidy
how can polyploidy in plants be induced
how can polyploidy be generated through selective breeding
what can triploidy be caused by (naturally)
how can triploidy be caused by dispermy
dispermy is the most common cause of human triploidy
