Why do blood types matter? - Natalie S. Hodge

Zakaj so krvne skupine pomembne? - Natalie S. Hodge

Translator: Nika Kotnik Reviewer: Klavdija Cernilogar

It's often said that despite humanity's many conflicts,

Pogosto rečemo, da kljub vsem konfliktom človeštva

we all bleed the same blood.

po žilah vsem teče ista kri.

Lepa misel, a ni čisto točna.

It's a nice thought but not quite accurate.

In fact, our blood comes in a few different varieties.

V bistvu kri obstaja v več različicah.

Our red blood cells contain a protein called hemoglobin

Rdeče krvničke vsebujejo protein imenovan hemoglobin,

ki veže kisik,

that binds to oxygen,

kar omogoča, da ga celice prenašajo po telesu.

allowing the cells to transport it throughout the body.

But they also have another kind of complex protein

A imajo še en kompleksen protein

on the outside of the cell membrane.

na zunanji strani membrane.

These proteins, known as antigens, communicate with white blood cells,

Ti proteini, imenovani antigeni, komunicirajo z belimi krvničkami,

immune cells that protect against infection.

imunskimi celicami, ki nas varujejo pred vnetji.

Antigens serve as identifying markers,

Antigeni služijo kot označevalci,

allowing the immune system to recognize your body's own cells

ki omogočajo imunskemu sistemu, da prepozna celice lastnega telesa,

namesto da bi jih napadel kot tujke.

without attacking them as foreign bodies.

The two main kinds of antigens, A and B, determine your blood type.

Dva glavna antigena, A in B, določata krvno skupino.

But how do we get four blood types from only two antigens?

A kako dobimo štiri krvne skupine iz samo dveh antigenov?

Well, the antigens are coded for by three different alleles,

Antigene kodirajo trije različni aleli,

varieties of a particular gene.

različice določenega gena.

While the A and B alleles code for A and B antigens,

Medtem ko alel A in B kodirata A in B antigena,

the O allele codes for neither,

alel O ne kodira nobenega

and because we inherit one copy of each gene from each parent,

in ker podedujemo eno kopijo gena od vsakega starša,

every individual has two alleles determining blood type.

ima vsak posameznik dva alela, ki določata krvno skupino.

Kadar sta različna,

When these happen to be different,

one overrides the other depending on their relative dominance.

eden prevlada nad drugim, odvisno od relativne dominance.

For blood types, the A and B alleles are both dominant, while O is recessive.

Za krvne skupine sta A in B alela oba dominantna, medtem ko je O recesiven.

So A and A gives you type A blood, while B and B gives you type B.

Tako A in A data krvno skupino A, medtem ko B in B data skupino B.

If you inherit one of each,

Če podedujete po enega od vsake,

the resulting codominance will produce both A and B antigens,

bo kodominanca proizvedla antigena A in B,

which is type AB.

kar da skupino AB.

The O allele is recessive,

Alel O je recesiven,

so either of the others will override it when they're paired,

zato bo prevladal eden od ostalih dveh

resulting in either type A or type B.

in rezultat bo krvna skupina A ali B.

But if you happen to inherit two Os, instructions will be expressed

Če pa podedujete dva O, bodo navodila narekovala,

that make blood cells without the A or the B antigen.

naj nastanejo krvne celice brez A ali B antigena.

Because of these interactions,

Zaradi teh interakcij lahko, če poznamo krvno skupino obeh staršev,

knowing both parents' blood types

lets us predict the relative probability of their children's blood types.

predvidimo relativno verjetnost krvne skupine otroka.

Why do blood types matter?

Zakaj so krvne skupine pomembne?

For blood transfusions,

Pri transfuzijah krvi

prava krvna skupina pomeni razliko med življenjem in smrtjo.

finding the correct one is a matter of life and death.

If someone with type A blood is given type B blood, or vice versa,

Če nekdo s krvno skupino A dobi kri s krvno skupino B ali obratno,

their antibodies will reject the foreign antigens and attack them,

bodo protitelesa zavrnila tuje antigene in jih napadla,

potentially causing the transfused blood to clot.

kar lahko povzroči strjevanje krvi.

A ker imajo ljudje s krvno skupino AB antigena A in B,

But because people with type AB blood produce both A and B antigens,

they don't make antibodies against them, so they will recognize either as safe,

nimajo protiteles proti njima, zato ju bodo prepoznali kot varna,

making them universal recipients.

zaradi česar so univerzalni prejemniki.

On the other hand,

Po drugi strani

people with blood type O do not produce either antigen,

pa ljudje s krvno skupino O ne proizvajajo nobenega antigena,

which makes them universal donors,

zato so univerzalni darovalci,

but will cause their immune system to make antibodies

a njihov imunski sistem bo proizvedel protitelesa,

that reject any other blood type.

ki bodo zavrnila katerokoli drugo krvno skupino.

Unfortunately, matching donors and recipients is a bit more complicated

Na žalost je ujemanje darovalcev in prejemnikov malo bolj zapleteno

due to additional antigen systems,

zaradi dodatnih antigenskih sistemov,

particular the Rh factor,

še posebej Rh faktorja,

named after the Rhesus monkeys in which it was first isolated.

ki je poimenovan po vrsti Rhesus opic, pri katerih so ga prvič izolirali.

Rh+ or Rh- refers to the presence or absence of the D antigen

Rh+ ali Rh- se navezuje na prisotnost ali odsotnost D antigena

of the Rh blood group system.

v sistemu Rh krvne skupine.

And in addition to impeding some blood transfusions,

Ne samo, da onemogoča nekatere transfuzije krvi,

it can cause severe complications in pregnancy.

lahko povzroči tudi hude zaplete v nosečnosti.

If an Rh- mother is carrying an Rh+ child,

Če Rh- mati nosi Rh+ otroka,

her body will produce Rh antibodies that may cross the placenta

bo njeno telo proizvedlo Rh- protitelesa, ki lahko skozi posteljico

and attack the fetus,

napadejo zarodek,

a condition known as hemolytic disease of the newborn.

kar poznamo kot hemolitično bolezen novorojenčka.

Some cultures believe blood type to be associated with personality,

Nekatere kulture verjamejo, da je krvna skupina povezana z osebnostjo,

čeprav za to ni znanstvenih dokazov.

though this is not supported by science.

And though the proportions of different blood types

In čeprav razmerja med krvnimi skupinami

vary between human populations,

med populacijami zelo variirajo,

scientists aren't sure why they evolved;

znanstveniki ne vedo, zakaj so se razvile;

perhaps as protection against blood born diseases,

morda kot zaščita pred boleznimi, ki se prenašajo s krvjo,

or due to random genetic drift.

ali zaradi naključne genetske spremembe.

Finally, different species have different sets of antigens.

Različne vrste imajo različne skupine antigenov.

In fact, the four main blood types shared by us apes

Pravzaprav štiri glavne krvne skupine, ki si jih človečnjaki delimo,

seem paltry in comparison to the thirteen types found in dogs.

niso nič v primerjavi s trinajstimi, ki jih najdemo pri psih.