Misplaced Pages

#13986

40-567: See text The sticklebacks are a family of ray-finned fishes , the Gasterosteidae which have a Holarctic distribution in fresh, brackish and marine waters. They were thought to be related to the pipefish and seahorses but are now thought to be more closely related to the eelpouts and sculpins . The stickleback family, Gasterosteidae, was first proposed as a family by the French zoologist Charles Lucien Bonaparte in 1831. It

80-470: A century sponge cells have been known to reassemble into new sponges after having been separated by forcing them through a sieve. Germline can refer to a lineage of cells spanning many generations of individuals—for example, the germline that links any living individual to the hypothetical last universal common ancestor , from which all plants and animals descend . Plants and basal metazoans such as sponges (Porifera) and corals (Anthozoa) do not sequester

120-457: A consensus over time. The naming of families is codified by various international bodies using the following suffixes: The taxonomic term familia was first used by French botanist Pierre Magnol in his Prodromus historiae generalis plantarum, in quo familiae plantarum per tabulas disponuntur (1689) where he called the seventy-six groups of plants he recognised in his tables families ( familiae ). The concept of rank at that time

160-443: A distinct germline, generating gametes from multipotent stem cell lineages that also give rise to ordinary somatic tissues. It is therefore likely that germline sequestration first evolved in complex animals with sophisticated body plans, i.e. bilaterians. There are several theories on the origin of the strict germline-soma distinction. Setting aside an isolated germ cell population early in embryogenesis might promote cooperation between

200-446: A family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to a lack of widespread consensus within the scientific community for extended periods. The continual publication of new data and diverse opinions plays a crucial role in facilitating adjustments and ultimately reaching

240-455: A genetic disorder, and of these, about 20% are due to newly arisen germline mutations . Epigenetic alterations of DNA include modifications that affect gene expression, but are not caused by changes in the sequence of bases in DNA. A well-studied example of such an alteration is the methylation of DNA cytosine to form 5-methylcytosine . This usually occurs in the DNA sequence CpG , changing

280-451: A nest from weeds held together by spiggin, a kidney secretion, then attract females to the nest. Females signal their readiness to mate with solitary rather than shoaling behaviour, a head-up posture; their bellies are also obviously distended with eggs. Courtship typically involves a zig-zag 'dance' where the male approaches the female in an erratic side-to-side pattern, and dorsal pricking of the female's abdomen. A female lays her eggs inside

320-500: A reference freshwater stickleback was described in 2012, along with set of genetic variants commonly found in 21 marine and freshwater populations around the world. Some variants, and several chromosome inversions, consistently distinguish marine and freshwater populations, helping identify a genome-wide set of changes contributing to repeated adaptation of sticklebacks to marine and freshwater environments. The adaptations seen in oceanic threespine sticklebacks make them an ideal organism for

360-858: A significant cause of DNA damages that, upon DNA replication , lead to mutations . 8-Oxoguanine , an oxidized derivative of guanine , is produced by spontaneous oxidation in the germline cells of mice, and during the cell's DNA replication cause GC to TA transversion mutations. Such mutations occur throughout the mouse chromosomes as well as during different stages of gametogenesis . The mutation frequencies for cells in different stages of gametogenesis are about 5 to 10-fold lower than in somatic cells both for spermatogenesis and oogenesis . The lower frequencies of mutation in germline cells compared to somatic cells appears to be due to more efficient DNA repair of DNA damages, particularly homologous recombinational repair, during germline meiosis . Among humans, about five percent of live-born offspring have

400-401: Is believed to be because larger females on average produce larger eggs, which leads to a greater offspring survival and fitness. In addition, male sticklebacks have also been observed to prefer females with more distended or bloated stomachs. The benefits of this is also due to larger eggs and thus offspring survival and fitness Female three-spined sticklebacks adjust their courting behaviour to

440-646: Is likely followed by replication-dependent dilution during embryonic days 11.5 to 13.5. At embryonic day 13.5, PGC genomes display the lowest level of global DNA methylation of all cells in the life cycle. In the mouse, the great majority of differentially expressed genes in PGCs from embryonic day 9.5 to 13.5, when most genes are demethylated, are upregulated in both male and female PGCs. Following erasure of DNA methylation marks in mouse PGCs, male and female germ cells undergo new methylation at different time points during gametogenesis. While undergoing mitotic expansion in

SECTION 10

#1732782761014

480-509: Is partly artificial and depends on particular circumstances and internal cellular mechanisms such as telomeres and controls such as the selective application of telomerase in germ cells, stem cells and the like. Not all multicellular organisms differentiate into somatic and germ lines, but in the absence of specialised technical human intervention practically all but the simplest multicellular structures do so. In such organisms somatic cells tend to be practically totipotent , and for over

520-668: Is possible because the red coloration can only be produced by males that are free of parasites. This is referred to in the Hamilton-Zuk hypothesis. However, there is also evidence that attractive male red coloration may be a faulty signal of male quality. Male sticklebacks that are more attractive to females due to carotenoid colorants may under-allocate carotenoids to their germline cells. Since carotinoids are beneficial antioxidants, their under-allocation to germline cells can lead to increased oxidative DNA damage to these cells. Therefore, female sticklebacks may risk fertility and

560-461: Is the far larger fifteen-spined stickleback ( Spinachia spinachia ), which can reach 22 cm (approx. 8.8 inches). Body form varies with habitat: sticklebacks in shallow lakes have developed a deep body specialized to enable feeding on benthic invertebrates, whilst those in deep oligotrophic lakes have adapted to feed on plankton and have a more slimlined body. Research has shown that Sticklebacks display distinct personality traits, specifically in

600-502: Is treated as the infraorder Gasterosteales within the suborder Cottoidei or as a sister clade to the Zoarcales in the order Zoarciformes. FishBase recognises 16 species in the family, grouped in five genera. However, several of the species have a number of recognised subspecies, and the taxonomy of the family is thought to be in need of revision. The family Gasterosteidae includes the following genera: Sticklebacks are endemic to

640-469: The Genera Plantarum of George Bentham and Joseph Dalton Hooker this word ordo was used for what now is given the rank of family. Families serve as valuable units for evolutionary, paleontological, and genetic studies due to their relatively greater stability compared to lower taxonomic levels like genera and species. Germline Germ cells pass on genetic material through

680-434: The behaviour of this fish were important in the early development of ethology as an example of a fixed action pattern . More recently, the fish have become a favourite system for studying the molecular genetics of evolutionary change in wild populations and a powerful "supermodel" for combining evolutionary studies at molecular, developmental, population genetic, and ecological levels. The nearly complete genome sequence of

720-414: The epigenome in order to form an egg or sperm. In the mouse, PGCs undergo DNA demethylation in two phases. The first phase, starting at about embryonic day 8.5, occurs during PGC proliferation and migration, and it results in genome-wide loss of methylation, involving almost all genomic sequences. This loss of methylation occurs through passive demethylation due to repression of the major components of

760-521: The DNA at the CpG site from CpG to 5-mCpG. Methylation of cytosines in CpG sites in promoter regions of genes can reduce or silence gene expression. About 28 million CpG dinucleotides occur in the human genome, and about 24 million CpG sites in the mouse genome (which is 86% as large as the human genome ). In most tissues of mammals, on average, 70% to 80% of CpG cytosines are methylated (forming 5-mCpG). In

800-421: The area of taking a risk, and, can be considered bold or shy. These personality traits were determined to directly influence if they would lead, and if discouraged, attempt to lead again. All stickleback species show similar, unusual mating behaviour. Freshwater males develop a red colouration, and although this may be seen in oceanic and benthic species these tend to remain dull-coloured. The male then constructs

840-461: The book's morphological section, where he delved into discussions regarding the vegetative and generative aspects of plants. Subsequently, in French botanical publications, from Michel Adanson 's Familles naturelles des plantes (1763) and until the end of the 19th century, the word famille was used as a French equivalent of the Latin ordo (or ordo naturalis ). In zoology ,

SECTION 20

#1732782761014

880-540: The family as a rank intermediate between order and genus was introduced by Pierre André Latreille in his Précis des caractères génériques des insectes, disposés dans un ordre naturel (1796). He used families (some of them were not named) in some but not in all his orders of "insects" (which then included all arthropods ). In nineteenth-century works such as the Prodromus of Augustin Pyramus de Candolle and

920-560: The germline may be passed to offspring, but changes in a somatic cell will not be. This need not apply to somatically reproducing organisms, such as some Porifera and many plants. For example, many varieties of citrus , plants in the Rosaceae and some in the Asteraceae , such as Taraxacum , produce seeds apomictically when somatic diploid cells displace the ovule or early embryo. In an earlier stage of genetic thinking, there

960-438: The latter tends to be seen in nematodes, as well as certain species of reptiles, birds, and fish. Autogamy is a term used to describe self pollination in plants. Cloning is a technique used to creation of genetically identical cells or organisms. In sexually reproducing organisms, cells that are not in the germline are called somatic cells . According to this definition, mutations , recombinations and other genetic changes in

1000-477: The methylation machinery. The second phase occurs during embryonic days 9.5 to 13.5 and causes demethylation of most remaining specific loci, including germline-specific and meiosis-specific genes. This second phase of demethylation is mediated by the TET enzymes TET1 and TET2, which carry out the first step in demethylation by converting 5-mC to 5-hydroxymethylcytosine (5-hmC) during embryonic days 9.5 to 10.5. This

1040-406: The mouse, by days 6.25 to 7.25 after fertilization of an egg by a sperm, cells in the embryo are set aside as primordial germ cells (PGCs). These PGCs will later give rise to germline sperm cells or egg cells. At this point the PGCs have high typical levels of methylation. Then primordial germ cells of the mouse undergo genome-wide DNA demethylation , followed by subsequent new methylation to reset

1080-463: The nest, where the male fertilises them. The male then guards the eggs until they hatch 7–14 days later (depending on temperature), and may continue to guard the fry after they hatch. This large investment in both the nesting site and guarding of the eggs limits the number of females a male can mate with however males spawn multiple times. This introduces the ability for selection to favor male mate choice . Some males die following spawning. Typically,

1120-505: The presence of strong and clearly isolated spines in their dorsal fins . An unusual feature of sticklebacks is that they have no scales, although some species have bony armour plates. The maximum size of the best-known species, the three-spined stickleback ( Gasterosteus aculeatus ), is about 4 inches, but few of them are more than 3 inches long. They mature sexually at a length of about 2 inches. Most other stickleback species are roughly similar in size or somewhat smaller. The only exception

1160-431: The process of sexual reproduction. This includes fertilization , recombination and meiosis . These processes help to increase genetic diversity in offspring. Certain organisms reproduce asexually via processes such as apomixis , parthenogenesis , autogamy , and cloning . Apomixis and Parthenogenesis both refer to the development of an embryo without fertilization. The former typically occurs in plants seeds, while

1200-491: The ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae , but that family is commonly referred to as the "walnut family". The delineation of what constitutes a family— or whether a described family should be acknowledged— is established and decided upon by active taxonomists . There are not strict regulations for outlining or acknowledging

1240-424: The risk of inbreeding . When gravid females are given the choice between a courting unfamiliar non-sibling and a familiar brother, they prefer to mate with the non-sibling and thus avoid the disadvantages that accompany incest . Eggs from inbred matings compared to eggs from outbred matings have a lower rate of fertilization and hatching, and fewer progeny survive to reproductive age. Niko Tinbergen 's studies of

Stickleback - Misplaced Pages Continue

1280-607: The sex with the greatest parental investment has the strongest mate preferences. Stickleback species exhibit mutual mate choice in which both the male and female have strong mate preferences. This is due in part to the strong parental investment on behalf of the male in guarding the eggs. Female sticklebacks show a strong preference to male stickleback with bright red coloration under their throats. Females mate both more often with males with brighter red coloration and give on average, larger eggs to be fertilized by these males. This preference has led to brighter red coloring. This association

1320-404: The somatic cells of a complex multicellular organism. Another recent theory suggests that early germline sequestration evolved to limit the accumulation of deleterious mutations in mitochondrial genes in complex organisms with high energy requirements and fast mitochondrial mutation rates. Reactive oxygen species (ROS) are produced as byproducts of metabolism. In germline cells, ROS are likely

1360-673: The study of parallel evolution. There is a sculpture in Kronstadt dedicated to stickleback, which saved thousands of city residents from starvation during the Leningrad Siege of World War II . Family (biology) Family ( Latin : familia , pl. : familiae ) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy . It is classified between order and genus . A family may be divided into subfamilies , which are intermediate ranks between

1400-534: The temperate zone and are most commonly found in the ocean, but some can be found in fresh water. The freshwater taxa were trapped in Europe , Asia , and North America after the Ice Age 10,000–20,000 years ago, and have evolved features different from those of the marine species. Sticklebacks are carnivorous, feeding on small animals such as insects, crustaceans and fish larvae. Sticklebacks are characterised by

1440-579: The three-spined stickleback, the large investment in both nesting site and guarding of eggs by males limits the number of females a male can mate with. This introduces the ability for selection to favor male mate choice. Male mate choice is rarely studied or observed in many species but multiple studies have confirmed male mate choice within stickleback species. Males show a choosiness similar to females as to what female they are willing to court and mate. Male sticklebacks have been observed to show preference towards female sticklebacks that are larger and longer. This

1480-419: The viability of their offspring by choosing redder, but more deteriorated partners with reduced sperm quality. Female mate choice has also been seen to be condition dependent. Females are almost always the more choosy sex in most species. Female sticklebacks though, have been found to be less choosy of mates when in poor physical condition and inversely, more choosy in good condition. In some species, such as

1520-402: Was a clear distinction between germline and somatic cells. For example, August Weismann proposed and pointed out, a germline cell is immortal in the sense that it is part of a lineage that has reproduced indefinitely since the beginning of life and, barring accident, could continue doing so indefinitely. However, it is now known in some detail that this distinction between somatic and germ cells

1560-695: Was long thought that the sticklebacks and their relatives made up a suborder, the Gasterosteoidei , of the order Gasterostiformes with the sea horses and pipefishes making up the suborder Syngnathoidei. More recent phylogenetic work has shown that the Gaterosteoidei is more closely related to the Zoarcoidei and the Cottoidei , which means that this taxon would belong in the order Scorpaeniformes . but in other phylogenetic classifications it

1600-488: Was not yet settled, and in the preface to the Prodromus Magnol spoke of uniting his families into larger genera , which is far from how the term is used today. In his work Philosophia Botanica published in 1751, Carl Linnaeus employed the term familia to categorize significant plant groups such as trees , herbs , ferns , palms , and so on. Notably, he restricted the use of this term solely within

#13986