Meiosis Flashcards
Meiosis
The type of nuclear division in which the number of chromosomes is halved.
Reproductive (sex) cell that fuses with another gamete during fertilisation
Gamete
Diploid
Cell or nucleus containing pairs of homologous chromosomes (two sets of chromosomes)
Cell or nucleus containing single, unpaired chromosomes (a single copy of each chromosome)
Haploid
Homologous chromosomes
A pair of chromosomes, one maternal and one paternal, that have the same gene loci and therefore determine the same features. They are not necessarily identical as may have different alleles. They are capable of pairing during meiosis.
The process whereby a chromatid breaks during meiosis and rejoins to the chromatid of its homologous chromosome so that their alleles are exchanged
Crossing over
A point at which paired chromosomes remain in contact during the first metaphase of meiosis and at which crossing over and exchange of genetic material occur between the strands.
Chiasmata
The rearrangement of genetic material, especially by crossing over in chromosomes.
Recombination
Independent assortment
The alleles of two (or more) different genes get sorted into gametes independently of one another. The allele a gamete receives for one gene does not influence the allele received for another gene. This is because homologous chromosomes line up in random orientations at the middle of the cell at metaphase as they prepare to separate, meaning that the same parent cell can produce different combinations of chromosomes in the daughter cells.
Independent segregation
During the formation of gametes, each gamete receives just one gene copy, which is selected randomly. Each pair of alleles segregates independently of the other pairs and all possible combinations of alleles can occur in the resulting gametes.
Differences between individuals. It can be interspecific (between different species) or intraspecific variation (between individuals of the same species).
Variation
