A meiocyte is a type of cell that differentiates into a

gamete A gamete ( ) is a Ploidy#Haploid and monoploid, haploid cell that fuses with another haploid cell during fertilization in organisms that Sexual reproduction, reproduce sexually. Gametes are an organism's reproductive cells, also referred to as s ...

through the process of

meiosis Meiosis () is a special type of cell division of germ cells in sexually-reproducing organisms that produces the gametes, the sperm or egg cells. It involves two rounds of division that ultimately result in four cells, each with only one c ...

. Through meiosis, the

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...

meiocyte divides into four genetically different

haploid Ploidy () is the number of complete sets of chromosomes in a cell (biology), cell, and hence the number of possible alleles for Autosome, autosomal and Pseudoautosomal region, pseudoautosomal genes. Here ''sets of chromosomes'' refers to the num ...

gametes.Libeau, P., Durandet, M., Granier, F., Marquis, C., Berthomé, R., Renou, J. P., Taconnat-Soubirou, L., and Horlow, C. (2011)
Gene expression profiling of ''Arabidopsis'' meiocytes.
''Plant Biology'' 13, 784-793.Roig, I., Brieno-Enriquez, M. A., Caldes, M. G. (2011)
Meiosis in a bottle: new approaches to overcome mammalian meiocyte study limitations.
''Genes'' 2, 152-168. The control of the meiocyte through the meiotic cell cycle varies between different groups of organisms.

Yeast

The process of meiosis has been extensively studied in model organisms, such as

yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom (biology), kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are est ...

.Yang, X., Makaroff, C. A., and Ma, H. (2003)
The Arabidopsis ''MALE MEIOCYTE DEATH1'' gene encodes a PHD-finger protein that is required for male meiosis.
''The Plant Cell'' 15, 1281-1295. Because of this, the way in which the meiocyte is controlled through the meiotic cell cycle is best understood in this group of organisms. A yeast meiocyte that is undergoing meiosis must pass through a number of checkpoints in order to complete the cell cycle. If a meiocyte divides and this division results in a

mutant In biology, and especially in genetics, a mutant is an organism or a new genetic character arising or resulting from an instance of mutation, which is generally an alteration of the DNA sequence of the genome or chromosome of an organism. It i ...

cell, the mutant cell will undergo

apoptosis Apoptosis (from ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemistry, Biochemical events lead to characteristic cell changes (Morphology (biol ...

and, therefore, will not complete the cycle. In natural populations of the yeast ''

Saccharomyces cerevisiae ''Saccharomyces cerevisiae'' () (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungal microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have be ...

'',

meiocytes produce haploid cells that then mainly undergo either clonal reproduction, or selfing (intratetrad mating) to form progeny diploid meiocytes. When the ancestry of natural ''S. cerevisiae'' strains was analyzed, it was determined that formation of diploid meiocytes by

outcrossing Out-crossing or out-breeding is the technique of crossing between different breeds. This is the practice of introducing distantly related genetic material into a breeding line, thereby increasing genetic diversity. Outcrossing in animals Out ...

(as opposed to

inbreeding Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely genetic distance, related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genet ...

or selfing) occurs only about once every 50,000 cell divisions. These findings suggest that the principal adaptive function of meiocytes may not be related to the production of

genetic diversity Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species. It ranges widely, from the number of species to differences within species, and can be correlated to the span of survival for a species. It is d ...

that occurs infrequently by outcrossing, but rather may be mainly related to recombinational repair of DNA damage (that can occur in meiocytes at each mating cycle).Bernstein H, Byerly HC, Hopf FA, Michod RE. Genetic damage, mutation, and the evolution of sex. Science. 1985 Sep 20;229(4719):1277-81. doi: 10.1126/science.3898363. PMID 3898363

Animal

The

animal Animals are multicellular, eukaryotic organisms in the Biology, biological Kingdom (biology), kingdom Animalia (). With few exceptions, animals heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, ...

meiotic cell cycle is very much like that of yeast. Checkpoints within the animal meiotic cell cycle serve to stop mutant meiocytes from progressing further within the cycle. Like yeast meiocytes, if an animal meiocyte differentiates into a mutant cell, the cell will undergo apoptosis.

Plant

The meiotic cell cycle in

plants Plants are the eukaryotes that form the kingdom Plantae; they are predominantly photosynthetic. This means that they obtain their energy from sunlight, using chloroplasts derived from endosymbiosis with cyanobacteria to produce sugars f ...

is very different from that of yeast and animal cells. In plant studies, mutations have been identified that affect meiocyte formation or the process of meiosis. Most meiotic mutant plant cells complete the meiotic cell cycle and produce abnormal microspores. It appears that plant meiocytes do not undergo any checkpoints within the meiotic cell cycle and can, thus, proceed through the cycle regardless of any defect. By studying the abnormal microspores, the progression of the plant meiocyte through the meiotic cell cycle can be investigated further.Wang, D., Skibbe, D. S., and Walbot, V. (2011)
Maize ''csmd1'' exhibits pre-meiotic somatic and post-meiotic microspore defects but sustains anther growth.
''Sex Plant Reprod'' 24, 297-306.

Mammalian infertility

Researching meiosis in

mammals A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle e ...

plays a crucial role in understanding human

infertility In biology, infertility is the inability of a male and female organism to Sexual reproduction, reproduce. It is usually not the natural state of a healthy organism that has reached sexual maturity, so children who have not undergone puberty, whi ...

. Meiosis research within mammal populations is restricted due to the fundamental nature of meiosis. In order to study mammalian meiosis, a culture technique that would allow for this process to be observed live under a microscope would need to be identified. By viewing live mammalian meiosis, one can observe the behavior of mutant meiocytes that may possibly compromise infertility within the particular organism. However, because of the size and small number of meiocytes, collecting samples of these cells has been difficult and is currently being researched.

References

{{Reflist Cell cycle