Dzokubereka nerevane chaivo kukosha meiosis

The dzokubereka kushanda muviri rinoitwa munguva maererano pakati gametes maviri (utachiona masero) muna chiitiko uye haizopereri kuvandudzika zygote chikamu muviri - zai. In vabereki masero pabonde vane imwe akagadzirwa N-okutodza. Akadana haploid. Zygote ari kutora kutaridza izvi, ndizvo foni diploid, kureva, chromosome nhamba 2n ikoko: mumwe rwaamai uye mumwe yemadzibaba. Biological meiotic nokupesana chaiyo kukosha sezvo ari muchitokisi kunoratidzwa pakuti kuvonga payo, sero haploid aumba kubva diploid masero.

tsananguro

Meiosis mu zvipenyu rinonzi mitosis mutsa; nokuda kwayo diploid somatic mumasero dzokubereka mumasero vari rakakamurwa 1n gametes. Kana tsanga iri nourume, pane Fusion kuti gametes. Saka, zviri apore 2n chromosome yakatarwa. Meaning of meiosis ndiko kuitira Kuchengetedzwa yokusafa neimwe mhando zvipenyu okutodza uye rakakodzera kwazvo DNA.

tsananguro

Meiosis - zvichiitika chichiitwa. Inoitwa zviviri kuparadzanise successively kutevera mumwe: meiosis I uye meiosis II. Mumwe nomumwe kwemasayendisiti, akavapindurawo, chinosanganisira prophase, metaphase, anaphase, telophase. Weboka meiosis kana meiosis I wokutanga, sezvikamu uwandu okutodza, i.e. pane Chiitiko paiya inonzi rutapudzo nokupesana. Kana inguva chechipiri meiosis kana meiosis II, masero haploid hakuiti angavhundutsira kuchinja, yava akaponeswa. Izvi anonzi equational kupesana.

All masero ari padariro meiosis, takura mamwe mashoko pamwero wokuchinja zviratidzo.

• Meiotic prophase wokutanga - Danho mberi akamonyoroka chromatin uye inotungamirwa okutodza. Panoperera kwazvo kunzwisisa ichi chiito majini zvinhu chipo wayo yepakutanga muchimiro - 2n2 okutodza.
• Metaphase anouya - anouya uye kufadza nenhanho akamonyoroka. The majini zvinhu ichiri handishanduki.
• Anaphase pamusoro meiosis achabatsirwa zvinoderedza. peya nerimwe kwevabereki okutodza anopa mumwe ayo mwanasikana masero. Genetic zvinhu nechakatsinhiwa mu sezvamunoita, sezvo chromosome nhamba yakanga hafu kuti: nomumwe danda muchitokisi inodikanwa 1n2 chromosome.
• Telophase - danho apo achiumba chinoumba, akaparadzaniswa cytoplasm. Mwanasikana masero zvakasikwa, ndivo 2 uye mumwe nomumwe chromatids maviri. kureva akaisawo okutodza mune haploid navo.
• Uyezve interkinesis vakachengeta, zvishoma pakati rokutanga uye rechipiri padanho meiosis. The maviri mwanasikana masero vagadzirira kupinda Danho rechipiri meiosis, kunoitika maererano chete mashandiro souya mitosis.

Naizvozvo zvipenyu kukosha meiosis chiri chokuti tichifambirana wayo wechipiri zvigadziriswe kunzwisisa kare vakaumba masero haploid 4 - 1n1 okutodza. Kureva, mumwe diploid mai Sero anopa upenyu kuno mana - mumwe haploid chromosome yakatarwa. Mune rimwe yokutanga meiotic dhigirii danho kuvabereki zvinhu recombines, uye danho rechipiri rinoitwa kufamba okutodza uye chromatids kune zvakasiyana matanda muchitokisi. kufamba izvi - kwaibva kushanduka uye uwandu hwakasiyana-siyana kuti intraspecific.

zvabuda

Saka, zvipenyu kukosha meiosis, zvechokwadi chikuru. Chokutanga, zvinofanira kucherechedzwa sezvo huru, chikuru pavaipfuura Genesisi ose gametes. Meiosis kunosimbiswa kuchinjwa magene mashoko kubva muviri mhando mumwe, chero kuti bereka pabonde nevanhu. Meiosis runoita intraspecific anofambidzana kuitika nokuti Masero mwanasikana akasiyana kwete chete kubva vabereki asiwo kusiyana.

Uyezve, zviri zvipenyu kukosha meiosis ine pakupa kuderedza nhamba okutodza mune nguva apo utachiona masero vari aumba. Meiosis chendangariro haploid yavo; panguva iyo muchangosangana iri zygote diploid chromosome maumbirwo anodzorerwa.