Male chromosomes. A kan Y-chromosome cewa rinjayar da shi ne alhakin abin da?

A batun kayyade bincike - da mamaki na gadar hali da bambancin. American Scientist T-X. Morgan halitta chromosome ka'idar gadar hali, tabbatar da cewa kowane jinsin iya fahince wasu karyotypes cewa yana dauke da wadannan iri chromosomes kamar yadda somatic da jam. Recent wakilta wani raba biyu ya bambanta a su maza da mãtã. A cikin wannan labarin, za mu bincika yadda tsarin yana da namiji da mace chromosomes da kuma yadda suka kasance sunã sãɓa a tsakãninsu.

Mene ne wani karyotype?

Kowane cell dauke da core ne halin da wani adadin chromosomes. Shi ne ake kira mai karyotype. A jinsuna daban gaban tsarin raka'a gadar hali ne tsananin musamman, misali, mutum karyotype na 46 chromosomes a chimpanzee - 48 crayfish - 112. Kuma tsarin, size, siffar daban-daban daga cikin mutane da na wa daban-daban taxonomic halittun. Yawan chromosomes a cikin cell na jiki da ake kira diploid. Shi ne na hali somatic gabobin da kyallen takarda. Idan sakamakon maye gurbi karyotype canje-canje (msl, a marasa lafiya tare da Klinefelter Syndrome yawan chromosomes 47, 48), wadannan mutane sun rage haihuwa da kuma a mafi yawan lokuta ɓãci. Sauran hereditary cuta hade tare da jima'i chromosomes - Turner ciwo-Shereshevscky. Yana auku a matan da suka yi ba a cikin karyotype 46, da kuma 45 chromosomes. Wannan yana nufin cewa a cikin jima'i biyu ba ba biyu X chromosomes, amma daya kawai. Phenotypically bayyana a cikin underdevelopment na gonads, talauci ayyana sakandare jima'i halaye da kuma rasa haihuwa.

Somatic da kuma jima'i chromosomes

Sun bambanta duka biyu a siffar da wani sa na genes a cikin su. Human namiji chromosomes da kuma dabbobi masu shayarwa kunshe a cikin heterogametic jima'i biyu XY, samar da ci gaban na biyu firamare da sakandare da ɗa namiji halaye. A cikin maza, jima'i da tsuntsaye biyu qunshi biyu m ZZ namiji chromosomes kira homogametic. A bambanci ga chromosomes cewa sanin da jima'i da kwayoyin, hereditary tsarin karyotype ne m biyu a namiji da mace a. Su kira autosomes. A cikin mutum karyotype na 22 nau'i-nau'i. Namiji da mace jima'i chromosomes samar da 23 da biyu, saboda haka cikin karyotype mutum za a iya wakilta a matsayin janar dabara: 22 nau'i-nau'i daga autosomes + XY, da kuma mata - 22 nau'i-nau'i daga autosomes + XX.

meiosis

Samuwar jam sel - gametes, wanda aka kafa a mahaɗar tsakãninsu da zygote auku a cikin gonads: testes da kuma ovaries. Wadannan kyallen takarda sanya meiosis - aiwatar da cell division, sakamakon samuwar gametes dauke da haploid sa na chromosomes. Oogenesis ovarian oocyte maturation take kaiwa zuwa daya kawai jinsin: X + 22 autosomes da kuma maturation na spermatogenesis gomet samar da nau'i biyu na 22 autosomes kuma X + 22 autosomes + Y. A cikin mutane da baby ta jima'i aka ƙaddara a lokacin fe daga maniyyi da kwai nuclei da kuma dogara daga maniyyi karyotype.

Chromosome da ginshikai na jima'i kafiya

Mun riga dauke da ma'ana a cikinsa akwai jima'i kafiya a cikin mutane - a lokacin da hadi, kuma ya dogara a kan chromosomes na maniyyi. A wasu dabbobi mata da maza, suka sãɓã wa jũna a cikin yawan chromosomes. Alal misali, marine tsutsotsi, kwari, fara ne kawai a diploid maza, akwai daya kawai chromosome wata biyu daga jima'i, yayin da mace - biyu. Saboda haka, marine tsutsa haploid sa na chromosomes namiji atsirokantusa za a iya bayyana ta dabarbari: 0 + 5 chromosomes ko chromosome 5 + x, kuma da ɗiya mace ne a qwai, daya kadai sa na chromosomes 5 + x.

Abin da rinjayar da jima'i dimorphism?

Bugu da kari ga chromosomal akwai wasu hanyoyi na kayyade jima'i. Wasu halittu sun - rotifers, polychaetes - jima'i aka ƙaddara kafin hadewar gametes - hadi, a cikin abin da namiji da mace chromosomes samar da wata homologue biyu. Mãtan marine polychaete - dinofilyusa a lokacin oogenesis ta samar da iri biyu kwai. A farko - cikin kananan, matalauta gwaiduwa - ne maza ci gaba. Wasu - manyan, tare da wata babbar wadata da na gina jiki - ana amfani da shi don ci gaban mace. A zuma ƙudan zuma - mai yawan kwari Hymenoptera - mãtã nuna iri biyu qwai: diploid da haploid. Daga unfertilized qwai ci gaba a cikin maza - da drones da kuma hadu - mace suna ma'aikacin ƙudan zuma.

Hormones da su sakamako a kan samuwar jinsi

A cikin mutane, namiji gland - testes - samar da jima'i hormones testosterone jerin. Su shafi duka da ci gaban na farko jima'i halaye (ilimin Halittar Jiki tsarin ciki da waje al'aura gabobin), da kuma musamman Physiology. Ƙarƙashin rinjayar testosterone suna kafa sakandare jima'i halaye - tsarin da kwarangwal, musamman Figures, jiki jiki gashi, murya, da tsarin da maƙogwaro. The mace ta jiki ovaries nuna ba kawai sel haihuwar, amma kuma ba ji ba gani, kamar yadda gland shine yake secretions gauraye. Sex hormones kamar estradiol, progesterone, estrogen, taimakawa ga ci gaban waje da ciki al'aurar, jiki gashi rarraba mace irin, da tsara kwarara daga cikin hailar sake zagayowar da kuma ciki. Wasu vertabrate, kifi, annelids da halittar dabba mai kafafuwa ilimin aiki abubuwa samar da gonads, karfi da tasiri cikin ci gaban da firamare da kuma sakandare jima'i halaye, da kuma iri chromosomes a cikin wannan harka ba su da sosai tasiri a kan samuwar jinsi. Alal misali, larvae na marine polychaete - Bonelli - a ƙarƙashin rinjayar mace hormones gushe girma (size 1-3 mm) ne Dwarf maza. Suna zaune a al'aura fili na mace wanda da jiki tsawon har zuwa 1 mita. A kifi-cleaners dauke da namiji harems da dama mace. Mãtã, fãce da ovaries, ne farkon testes. Da zaran namiji ya mutu, daya daga cikin ƙulle mace daukan kan ta aiki (a cikin jikin ta fara rayayye ci gaba namiji gonads cewa samar da jima'i hormones).

jima'i tsari

A adam halittar jini, shi yana da za'ayi ta biyu sharudda: na farko ma'anar da dangantakar rudimentary gonads daga mugunya testosterone da mis hormone. Na biyu mulki nuna muhimmiyar rawa taka leda da Y-chromosome. Ɗa namiji da dukan daidai ilimin Halittar Jiki da kuma physiological cututtuka ci gaba a ƙarƙashin rinjayar kwayoyin halittu dake a cikin Y-chromosome. Interrelationship da kuma dogaro da biyu da dokoki na mutum jinsi ne da ake kira manufa na ci gaba: a cikin tayi, wanda shi ne bisexual (shi yana da rudiments na mace gland - Mullerian bututu da kuma namiji gonads - Wolffian bututu) bambantawa tayi zai gonad dogara a kan gaban ko rashinsa a cikin karyotype Y chromosome.

Halitta bayanai a cikin Y-chromosome

Nazarin jinsi, musamman T-X. Morgan, an gano cewa, a cikin mutane da kuma dabbobi masu shayarwa, da gene tsarin da X kuma Y chromosomes ne ba iri daya ba. Male chromosomes a cikin mutane da wasu alleles yanzu a kan X chromosome. Duk da haka, a cikin su gene pool wakilta SRY gene iko spermatogenesis, abu don samuwar ne da ɗa namiji. Hereditary cuta wannan gene a cikin tayi kaiwa zuwa ga cigaban da kwayoyin cuta - Suayra ciwo. A sakamakon haka, da mace tasowa daga irin wannan tayi ƙunshi XY karyotype jima'i biyu ko kuma kawai wani sashi na Y-chromosome dauke da gene wuri. Yana activates da ci gaban da gonads. Marasa lafiya mata ba su bambanta sakandare jima'i halaye, da kuma su ne infertile.

Y-chromosome da kwayoyin cututtuka

Kamar yadda muka gani a baya, namiji chromosome daban-daban daga X-chromosome matsayin size (shi ne karami) da kuma siffar (a ƙugiya irin). Har ila yau, ga ta, da kuma takamaiman sa kwayoyin halitta. Alal misali, a maye gurbi na daya daga cikin kwayoyin halittu a cikin chromosome ne phenotypically bayyana bayyanar m gashi cuta a rafani. Wannan yanayin ne halayyar kawai ga maza. An sani hereditary cuta lalacewa ta hanyar wani chromosomal maye gurbi kamar Klinefelter ciwo. The rashin lafiya mutum ne a cikin karyotype karin mace ko namiji chromosomes: XXY ko HHUU. Babban Hatsari alama ne pathological girma na mammary gland, osteoporosis, rashin haihuwa. A cuta ne quite na kowa: a kowane 500 jariri boys 1 haƙuri.

A takaice, za mu lura cewa a cikin mutane kamar yadda a wasu dabbobi masu shayarwa, da jima'i da kwayoyin da aka kaddara a wannan lokacin na hadi, saboda a wasu hade da wani zygote X kuma Y jima'i chromosomes.