sex chromosome

WordNet

1. tell the sex (of young chickens)
2. the properties that distinguish organisms on the basis of their reproductive roles; "she didnt want to know the sex of the foetus" (同)gender, sexuality
3. all of the feelings resulting from the urge to gratify sexual impulses; "he wanted a better sex life"; "the film contained no sex or violence" (同)sexual urge
4. either of the two categories (male or female) into which most organisms are divided; "the war between the sexes"
5. a threadlike strand of DNA in the cell nucleus that carries the genes in a linear order; "humans have 22 chromosome pairs plus two sex chromosomes"
6. having sexual differentiation
7. characterized by sexuality; "highly sexed"

PrepTutorEJDIC

1. 〈U〉〈C〉『性』,性別 / 《the~》《形容詞を伴い集合的に》『男性』,『女性』 / 〈U〉(男女(雌雄)間の)相違[の意識] / 〈U〉性に関する事柄(情報) / 〈U〉性交 / 〈ひよこなど〉‘の'性別を見分ける
2. 染色体

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/12/25 19:46:21」(JST)

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Human male XY chromosomes after G-banding

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An allosome (also referred to as a sex chromosome, heterotypical chromosome, heterochromosome, or idiochromosome) is a chromosome that differs from an ordinary autosome in form, size, and behavior. The human sex chromosomes, a typical pair of mammal allosomes, determine the sex of an individual created in sexual reproduction. Autosomes differ from allosomes because autosomes appear in pairs whose members have the same form but differ from other pairs in a diploid cell, whereas members of an allosome pair may differ from one another and thereby determine sex.

Placement

In humans, each cell nucleus contains 23 pairs of chromosomes, a total of 46 chromosomes. The first 22 pairs are called autosomes which look exactly the same in both males and females. The 23rd pair of chromosomes is called an allosome. These sex chromosomes usually differ between males and females. females have two copies of the X chromosome, while males have one X chromosome and one Y chromosome. The X chromosome is always present as the 23rd chromosome in the ovum, while either X or Y chromosomes can be present in an individual sperm.

Sex determination

Main article: Sex-determination system

See also: Sexual differentiation in humans

All diploid organisms with allosome-determined genders get half of their allosomes from each of their parents. In mammals, females are XX, they can pass along either of their X’s, and since the males are XY they can pass along either an X or a Y. For a mammal to be considered a female, the individual must receive an X chromosome from both parents, whereas to be considered a male, the individual must receive a X chromosome from their mother and a Y chromosome from their father. It is thus the male’s sperm that determines the sex of each offspring in humans.

Medical applications

Allosomes not only carry the genes that determine male and female traits, but also those for some other characteristics as well. Genes that are carried by either sex chromosome are said to be sex linked. Sex-linked diseases are passed down through families through one of the X or Y chromosomes. Since only men inherit Y chromosomes, they are the only ones to inherit Y-linked traits. Men and women can get the X-linked ones since both inherit X chromosomes.

An allele is either said to be dominant or recessive. Dominant inheritance occurs when an abnormal gene from one parent causes disease even though the matching gene from the other parent is normal. The abnormal allele dominates. Recessive inheritance is when both matching genes must be abnormal to cause disease. If only one gene in the pair is abnormal, the disease does not occur, or is mild. Someone who has one abnormal gene (but no symptoms) is called a carrier. A carrier can pass this abnormal gene to his or her children. X chromosome carry about 1500 genes, more than any other chromosome in the human body. Most of them code for something other than female anatomical traits. Many of the non-sex determining X-linked genes are responsible for abnormal conditions. The Y chromosome carries about 78 genes. Most of the Y chromosome genes are involved with essential cell house-keeping activities and sperm production. Only one of the Y chromosome genes, the SRY gene, is responsible for male anatomical traits. When any of the 9 genes involved in sperm production are missing or defective the result is usually very low sperm counts and infertility. Examples of mutations on the X chromosome include more common diseases such as color blindness, hemophilia, and fragile-X syndrome.

• Color blindness or color vision deficiency is the inability or decreased ability to see color, or perceive color differences, under normal lighting conditions. Color blindness affects many individuals in the population. There is no actual blindness, but there is a deficiency of color vision. The most usual cause is a fault in the development of one or more sets of retinal cones that perceive color in light and transmit that information to the optic nerve. This type of color blindness is usually a sex-linked condition. The genes that produce photopigments are carried on the X chromosome; if some of these genes are missing or damaged, color blindness will be expressed in males with a higher probability than in females because males only have one X chromosome.
• Hemophilia refers to a group of bleeding disorders in which it takes a long time for the blood to clot. This is referred to as X-Linked recessive. Hemophilia is much more common in males than females because males are hemizygous. They only have one copy of the gene in question and therefore express the trait when they inherit one mutant allele. In contrast, a female must inherit two mutant alleles, a less frequent event since the mutant allele is rare in the population. X-linked traits are maternally inherited from carrier mothers or from an affected father. Each son born to a carrier mother has a 50% probability of inheriting the X-chromosome carrying the mutant allele.
  • Queen Victoria was a carrier of the gene for hemophilia. She passed on the harmful allele to one of her four sons and at least two of her five daughters. Her son Leopold had the disease and died at age 30. As a result of marrying into other European royal families, the princesses Alice and Beatrice spread hemophilia to Russia, Germany, and Spain. By the early 20th century, ten of Victoria's descendents had hemophilia. All of them were men, as expected.
• Fragile X syndrome is a genetic condition involving changes in part of the X chromosome. It is the most common form of inherited intellectual disability (mental retardation) in males. It is caused by a change in a gene called FMR1. A small part of the gene code is repeated on a fragile area of the X chromosome. The more repeats, the more likely there is to be a problem. Males and females can both be affected, but because males have only one X chromosome, a single fragile X is likely to affect them more. Most fragile-X males have large testes, big ears, narrow faces, and sensory processing disorders that result in learning disabilities.

Other complications include:

• 46,XX testicular disorder of sex development, also called XX male syndrome, is a condition in which individuals with two X chromosomes in each cell, the pattern normally found in females, have a male appearance. People with this disorder have male external genitalia. In most people with 46,XX testicular disorder of sex development, the condition results from an abnormal exchange of genetic material between chromosomes (translocation). This exchange occurs as a random event during the formation of sperm cells in the affected person's father. The SRY gene (which is on the Y chromosome) is misplaced in this disorder, almost always onto an X chromosome. Anyone with an X chromosome that carries the SRY gene will develop male characteristics despite not having a Y chromosome.

See also

• Fisher's principle
• Haldane's rule
• XY sex-determination system
• ZW sex-determination system
• X0 sex-determination system

References

UpToDate Contents

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• 1. 性染色体異常 sex chromosome abnormalities
• 2. ターナー症候群（性腺発育不全）の臨床症状および診断 clinical manifestations and diagnosis of turner syndrome gonadal dysgenesis
• 3. 先天性の細胞遺伝学的異常 congenital cytogenetic abnormalities
• 4. 外陰部異常を有する幼児の評価 evaluation of the infant with ambiguous genitalia
• 5. Cutis verticis gyrata

English Journal

• Estrogen receptor β expression in the mouse forebrain: Age and sex differences.

• Zuloaga DG, Zuloaga KL, Hinds LR, Carbone DL, Handa RJ.Author information Department of Basic Medical Sciences, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, 85004-2157.AbstractEstrogen receptors regulate multiple brain functions, including stress, sexual, and memory-associated behaviors as well as controlling neuroendocrine and autonomic function. During development, estrogen signaling is involved in programming adult sex differences in physiology and behavior. Expression of estrogen receptor α changes across development in a region-specific fashion. By contrast, estrogen receptor β (ERβ) is expressed in many brain regions, yet few studies have explored sex and developmental differences in its expression, largely because of the absence of selective reagents for anatomical localization of the protein. This study utilized bacterial artificial chromosome transgenic mice expressing ERβ identified by enhanced green fluorescent protein (EGFP) to compare expression levels and distribution of ERβ in the male and female mouse forebrain on the day of birth (P0), on postnatal day 4 (P4), and on P21. By using qualitative analysis, we mapped the distribution of ERβ-EGFP and found developmental alterations in ERβ expression within the cortex, hippocampus, and hypothalamic regions including the arcuate, ventromedial, and paraventricular nuclei. We also report a sex difference in ERβ in the bed nucleus of the stria terminalis, with males showing greater expression at P4 and P21. Another sex difference was found in the anteroventral periventricular nucleus of P21, but not P0 or P4, mice, in which ERβ-EGFP-immunoreactive cells were densely clustered near the third ventricle in females but not males. These developmental changes and sex differences in ERβ indicate a mechanism through which estrogens might differentially affect brain functions or program adult physiology at select times during development. J. Comp. Neurol. 522:358-371, 2014. © 2013 Wiley Periodicals, Inc.
• The Journal of comparative neurology.J Comp Neurol.2014 Feb;522(2):358-71. doi: 10.1002/cne.23400.
• Estrogen receptors regulate multiple brain functions, including stress, sexual, and memory-associated behaviors as well as controlling neuroendocrine and autonomic function. During development, estrogen signaling is involved in programming adult sex differences in physiology and behavior. Expression
• PMID 23818057

• Small RNAs in spermatogenesis.

• Yadav RP, Kotaja N.Author information Department of Physiology, Institute of Biomedicine, University of Turku, Kiinamyllynkatu 10, FIN-20520 Turku, Finland. Electronic address: ramprakash.yadav@utu.fi.AbstractSpermatogenesis is characterized by meiotic divisions and major morphological changes to produce spermatozoa that are capable of independent movement and fertilization of an egg. Male germ cell differentiation is governed by orchestrated, phase-specific gene expression patterns that are tightly controlled at transcriptional and post-transcriptional level. Post-transcriptional regulation of protein-coding mRNAs becomes prominent during the late steps of spermatogenesis when the compacting sperm nucleus becomes transcriptionally inhibited. Small non-coding RNAs are important regulators of gene expression that mainly function post-transcriptionally to control the properties of their target mRNAs. Male germ cells express several classes of small RNAs, including Dicer-dependent microRNAs (miRNAs) and endogenous small interfering RNAs (endo-siRNAs), as well as Dicer-independent piwi-interacting RNAs (piRNAs). Increasing evidence supports the essential role of small RNA-mediated RNA regulation in normal spermatogenesis and male fertility.
• Molecular and cellular endocrinology.Mol Cell Endocrinol.2014 Jan 25;382(1):498-508. doi: 10.1016/j.mce.2013.04.015. Epub 2013 Apr 28.
• Spermatogenesis is characterized by meiotic divisions and major morphological changes to produce spermatozoa that are capable of independent movement and fertilization of an egg. Male germ cell differentiation is governed by orchestrated, phase-specific gene expression patterns that are tightly cont
• PMID 23632103

Japanese Journal

• 急性骨髄性白血病の病型分類と染色体異常-東京女子医科大学病院血液内科の過去28年間300症例における解析-

• 岡田 美智子/宇佐美 明美/岡嶋 香/三浦 裕子/兒玉 聖子/志村 華絵/田中 紀奈/三橋 健次郎/石山 みどり/風間 啓至/吉永 健太郎/今井 陽一/志関 雅幸/森 直樹/寺村 正尚/泉二 登志子
• 東京女子医科大学雑誌 83(E2), E539-E547, 2013-03-31
• 28年間に亘り、染色体分析を行ってきた当科の急性骨髄性白血病(AML)300例の分析結果を報告する。症例の内訳はWHO分類で特定の遺伝子異常を有するAMLとして、t(8;21)が25例、t(15;17)が36例、inv(16)が8例、t(9;11)が2例、t(6;9)が1例あった。そしてFAB分類のRAEB-T(RAEB in transformation、骨髄芽球比率20%以上30%未満の不応性 …
• NAID 110009575063

• Evolution of sex chromosomes ZW of Schistosoma mansoni inferred from chromosome paint and BAC mapping analyses.

• Hirai Hirohisa,Hirai Yuriko,Loverde Philip T
• Parasitology international 61(4), 684-689, 2012-12-00
• … Chromosomes of schistosome parasites among digenetic flukes have a unique evolution because they exhibit the sex chromosomes ZW, which are not found in the other groups of flukes that are hermaphrodites. … We conducted molecular cytogenetic analyses for investigating the sex chromosome evolution using chromosome paint analysis and BAC clones mapping. …
• NAID 120004873970

• Sex Identification of Newly Hatched Chicks by Fluorescence in situ Hybridization using a W-specific DNA Probe in Feather Follicle Cells

• SOHN Sea H.,CHO Eun J.,KANG Bo S.
• The journal of poultry science 49(4), 231-236, 2012-10-25
• NAID 10031120748

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拡張検索	「sex chromosome disorder」「sex chromosome aberration」「sex chromosome abnormality」
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「sex chromosome disorder」

　　[★]

• 性染色体疾患、性染色体異常

関

sex chromosome aberration、sex chromosome abnormality

「sex chromosome aberration」

　　[★]

• 性染色体異常

関

sex chromosome abnormality、sex chromosome disorder

「sex chromosome abnormality」

　　[★]

• 性染色体異常

関

sex chromosome aberration、sex chromosome disorder

「sex」

　　[★]

• n.

• 性、(肉体的な)性別、性交

関

coital、coition、coitus、copulation、gender、intercourse、sexual intercourse、sexuality、venereal