polyploid Flashcards
what causes polyploidy?
complete nondisjunction at MI or MII
what is polyploidy
organisms with multiples of n
what is endopolyploidy
diploid animals may produce polyploid tissues by undergoing DNA replication multiple times without cell division
what is the purpose of endopolyploidy
it allows enhancement of product of specific gene products
what issues can occur with triploid organisms
they are often sterile because they have an uneven amount of homologous chromosomes and cannot undergo meiosis properly
what types of gametes do triploid plants produce?
they typically produce highly aneuploid gametes due to unequal segregation of homologous chromosomes
what is allotetraploid
it is an organism that contains two complete sets of chromosomes from two different species
is an allotetraploid sustainable
yes, each homolog has a pair to line up with in meiosis
what is alloploidy
changes in # of chromosome sets due to interspecies crosses
what is autopolyploidy
multiple sets of chromosomes from the same species
how does autopolyploid occur?
nondisjunction occurs in both parents and they combine their 2n gametes to make a 4n individual with chromosome sets from individuals of the same species
why is an autotetraploid viable
each homolog has a pair to line up with
what types of polyploids are viable and which are not? (regardless if it is auto or allo)
even numbers (except allodiploid) are always viable
odd numbers are not
what is an allodiploid
it is an alloploid with one set of chromosomes from different species (each gamete from different species to make a 2n)
why is a mule, an allodiploid, sterile?
it is because of uneven homologous pairs
chromosomes in different species will undergo different chromosomal arrangements and translocations which makes it difficult for the chromosomes to pair in meiosis
true or false, allodiploid organisms are sterile because they are triploid
false, they are not triploid, it is due to the chromosomal arrangements across species and potential uneven amounts of chromosomes
true or false the mule is a hybrid of a horse and donkey. the reason why it is sterile is that there are three copies of the homologous chromosomes so they don’t segregate properly
false, they are not triploid
