Kungani Uzwela Ukudlula Abantu Abaningi

Ngabe uzizwa uzwela kakhulu ezinhlungwini kunabantu abaningi? Ukuthi uphendula kwizisusa ezibuhlungu ngokujule nangamandla kakhulu kunabanye abaningi? Ngokumangazayo, isisekelo salesi senzwa sezinzwa sisekelwe ku-DNA yakho. Kepha hhayi ngendlela ocabanga ukuthi iyiyo. Kukholwe noma ungakukholwa, isizathu salokhu kuzwela kobuhlungu obukhulayo empeleni kungenxa yokuthi iphesenti elincane labantu banamuhla linezinhlobo ezithile zofuzo ezavela kumaNeanderthals.

Kunjalo, amaNeanderthal. Ngempela, bekuyisikhathi esithile kwaziwa ukuthi abantu bahlangana namaNeanderthal ngaphambi kokuthi siqede abazala bethu abanomusa, abanobuhle bokuziphendukela kwemvelo baqothulwe ngenxa yolaka olukhulu lukaHomo sapiens nokuncintisana. Yize kunjalo, iHomo neanderthalensis isekhona ku “genome” yomuntu. Ngokombiko wakamuva oshicilelwe kulo magazini Isayensi , cishe u-2.6% we-DNA kubantu abaphilayo yazuzwa ngamaNeanderthals (Isayensi, Novemba, 2017).

Ngaphezu kwalokho, isifundo sakamuva kakhulu ku- I-Biology yamanje (Septhemba, 2020) uphakamisa ukuthi u-0.4% wabantu unokuhlukahluka kofuzo kweNeanderthal okwandisa ukuqhutshwa kwethonya lokuqina kanye nokwenziwa ezindleleni zobuhlungu bezindlela, ngaleyo ndlela kuholele ekukhuliseni ubuhlungu bezinhlungu kanye nobuhlungu obukhulu bokuzithoba kuleli qembu elincane labantu. Ngamagama alula, lokhu kusho ukuthi izigidi ezingama-31.2 zabantu abakhona manje abangu-7.8 billion - oyedwa kwabangu-250 - bathola ubuhlungu obukhulu kakhulu kunabantu abaningi kakhulu. Ngempela, abanye abantu bayakwazi ukubona nokuzwa ubukhulu nobuningi bezinhlungu njenge-sommelier bungabona ubunzima, izingqimba, nezinto ezithile ewayinini elimnandi.

Ukuthola ukuqonda okukhulu kwalolu cwaningo, kuyasiza ukwazi okuncane ngokuqonda kobuhlungu, nokuthi izinzwa zezinzwa zisebenza kanjani futhi ziphendula kanjani ezintweni eziyingozi. Okokuqala, igama lobuchwepheshe lokubona ubuhlungu liyi-nociception. Lokhu kungukuhlangenwe nakho okukhuthazayo kobuhlungu noma okulimazayo. Ngaphezu kwalokho, kunezinhlobo eziningana zesikhuthazi esinciphisa ubuhlungu: ukushisa (ukushisa nokubanda), imishini (ukucindezela nokuphina), namakhemikhali (ubuthi nobuthi).

Ngaphezu kwalokho, kuneziphetho zezinzwa eziguqulwe ngokukhethekile ezibizwa ngokuthi ama-nociceptors athola futhi aphendule kulezi zinto ezingaba yingozi ngokuthumela amasiginali we-electrochemical ezintanjeni zezinzwa ebuchosheni ngendlela yomgogodla. Le micu yezinzwa yakhiwe ngamangqamuzana akhethekile aguqule ikhono lokuthola, ukuthola, ukuhlanganisa, ukuhlanganisa, nokuphendula kwizisusa ezahlukahlukene ngokuthumela amasiginali awo kuzinhloso ezithile kuwo wonke umzimba. Lokhu kubizwa ngokuthi ukudubula kwemizwa noma ukusabalalisa isignali yayo kwamanye amaseli ezinzwa noma izicubu ezinjengemisipha, izindlala, uhlelo lwe-vascular, nezitho.

Ezingeni lamangqamuzana, lokhu kungenzeka ngoba, lapho kusebenze, amangqamuzana ezinzwa (noma ama-neuron lapho ebhekisa ebuchosheni nakumgogodla) ayakwazi ukushintshanisa ama-ion akhokhiswa ugesi kuwo wonke ulwelwesi lwawo ngamashaneli wamangqamuzana abizwa ngokuthi ama-ionophores (ngokwezwi nezwi "i-ion carrier"). Lapho ulwelwesi lwe-nerve cell lushintsha ngokushesha ama-ion e-extracellular sodium (okungukuthi, i-sodium egeza iseli) ne-potassium yayo engaphakathi (okungukuthi, i-potassium ebanjwe ngaphakathi kweseli) kuphumela kugagasi lwe-electrochemical olusakazeka ngokuqagela kwezinzwa (okuvame ukubizwa ngokuthi ama-axon) njengogesi ohamba ngentambo. Lapho lesi sifinyelelo sezinzwa sifinyelela ezinhlosweni zaso, sibangela ukuqhuma kwemicimbi egcina iholele ekuphenduleni kanye / noma ekuboneni okuqondayo.

Ngokuya ngocwaningo oluphawulwe ngenhla, kubonakala sengathi abantu abane-gene ye-Neanderthal banama-nociceptors anama-ionophores abo alungele ukuvula isimo. Ngakho-ke, ukushukunyiswa okuncane kakhulu kuzodala izimpawu zesibindi kubantu abazuze ifa lesizalo ngokuhlobene nabantu abangenawo. Empeleni, lokhu kusho ukuthi abantu abanegciwane le-Neanderthal bathola ukuzwa ubuhlungu. Kuyathakazelisa ukuthi futhi kukhonjisiwe ukuthi ubuhlungu obungokomzwelo noma bengqondo buthintelwa yizifunda ezifanayo zobuchopho ezilawula i-nociception engokomzimba. Ngenkathi kungekho datha (okwamanje) exhumanisa isakhi sofuzo seNeanderthal nociceptive ekukhuliseni ukucindezeleka ngokomzwelo, kungenzeka ukuthi ucwaningo lwesikhathi esizayo luzoveza ukuxhumana.

Khumbula: Cabanga kahle, Yenza kahle, Zizwe uphilile, Uphile!

Imininingwane 2020 uClifford N. Lazarus, Ph.D. Lokhu okuthunyelwe kwenzelwe ulwazi kuphela. Akuhloselwe ukuba esikhundleni sosizo oluvela kochwepheshe bezempilo abaqeqeshiwe. Izikhangiso ezikulokhu okuthunyelwe azibonisi imibono yami futhi azivunyelwe yimina.