Polyploidy

Polyploidy

Where an organism has more than two sets of chromosomes

Non-Disjunction

A process by which homologous chromosome pairs fail to separate during meiosis; may result in 2n

What does Polyploidy result in?

Instant Speciation as the polyploids WILL NOT be able to reproduce with the original population

Autopolyploidy

When polyploidy occurs in the same species due to non-disjunction; result in sterile hybrid 3n, or fertile hybrid 4n, 6n etc

Allopolyploidy

Occurs via the mating of two different species who are closely related in order to produce a hybrid. The resulting hybrid maybe sterile as it does not have homologous pairs of chromosomes, unable to form gametes.

Hybrid

an offspring produced from a cross between parents of different species or sub-species

Hybrid Zones

areas where genetically distinct populations meet, mate, and leave offspring of mixed ancestry.

Can a fertile hybrid be produced as a result of Allopolyploidy?

It can, only if that sterile hybrid goes through non-disjunction again to produce a fertile hybrid: 4n, 6n etc

What are the advantages of Polyploids?

Usually have larger cells which result in larger or resistant plants, with better characteristics than their diploid counterparts. They also have larger seeds (better for agriculture), and larger flowers (horticulture).

What advantages also come with Polyploids?

The uneven chromosome hybrids are sterile, thus having no seeds in resulting fruits, and also have a greater range of adaptations resulting from the other characteristics received from the different species.

reinforcement

natural selection favors each populations separate traits