How Mendel's pea plants helped us understand genetics - Hortensia Jiménez Díaz

Kako su Mendelove biljke graška pomogle da razumemo genetiku - Hortensija Himenes Dijaz

Translator: Andrea McDonough Reviewer: Bedirhan Cinar

Prevodilac: Mile Živković Lektor: Milenka Okuka

Ovih dana naučnici znaju kako nasleđujete karakteristike

These days scientists know

how you inherit characteristics from your parents.

od svojih roditelja.

They're able to calculate probabilities of having a specific trait

Mogu da izračunaju verovatnoću

da imate specifičnu osobinu

or getting a genetic disease

ili dobijete genetsku bolest

na osnovu informacija koje imaju

according to the information from the parents and the family history.

od roditelja i istorije porodice.

Ali kako je ovo moguće?

But how is this possible?

To understand how traits pass from one living being to its descendants,

Da bismo razumeli kako se osobine nasleđuju

od jednog živog bića na naslednike,

we need to go back in time to the 19th century

moramo da se vratimo u 19. vek

and a man named Gregor Mendel.

do čoveka zvanog Gregor Mendel.

Mendel was an Austrian monk and biologist

Mendel je bio austrijski monah i biolog

who loved to work with plants.

koji je voleo da radi s biljkama.

By breeding the pea plants he was growing in the monastery's garden,

Razmnožavanjem biljaka graška

koje je uzgajao u bašti manastira,

he discovered the principles that rule heredity.

otkrio je principe koji su osnova nasleđivanja.

U jednom od klasičnih primera,

In one of most classic examples,

Mendel combined a purebred yellow-seeded plant

Mendel je kombinovao biljku prave sorte i žutog semena

with a purebred green-seeded plant,

sa biljkom prave sorte i zelenog semena

and he got only yellow seeds.

i dobio je samo žuto seme.

He called the yellow-colored trait the dominant one,

Osobinu žutog semena nazvao je dominantnom

because it was expressed in all the new seeds.

jer je bila izražena u svom novom semenu.

Onda je novom hibridu žutog semena dozvolio da se samooplodi.

Then he let the new yellow-seeded hybrid plants self-fertilize.

And in this second generation, he got both yellow and green seeds,

U ovoj drugoj generaciji,

dobio je žuto i zeleno seme,

što je značilo da je zelena osobina bila skrivena

which meant the green trait had been hidden by the dominant yellow.

pod dominantnom žutom.

He called this hidden trait the recessive trait.

Ovu skrivenu osobinu nazvao je recesivnom.

Iz ovih rezultata, Mendel je zaključio

From those results, Mendel inferred

that each trait depends on a pair of factors,

da svaka osobina zavisi od para faktora,

one of them coming from the mother

od kojih je jedan od majke

and the other from the father.

a drugi od oca.

Sada znamo da se ovi faktori nazivaju alelama

Now we know that these factors are called alleles

and represent the different variations of a gene.

i predstavljaju različite varijacije gena.

Depending on which type of allele Mendel found in each seed,

U zavisnosti od toga koji tip alela

bi Mendel pronašao u svakom semenu,

we can have what we call a homozygous pea, where both alleles are identical,

imamo homozigotni grašak,

gde su obe alele identične

i imamo heterozigotni grašak

and what we call a heterozygous pea,

kada su dve alele drugačije.

when the two alleles are different.

This combination of alleles is known as genotype

Ova kombinacija alela poznata je kao genotip

and its result, being yellow or green,

i njen rezultat, zeleno ili žuto,

is called phenotype.

zove se fenotip.

Da bi se jasno predstavilo kako se raspoređuju alele

To clearly visualize how alleles are distributed amongst descendants,

u naslednicima,

možemo koristiti dijagram koji se zove Panetov kvadrat.

we can a diagram called the Punnett square.

You place the different alleles on both axes

Samo postavite različite alele na obe ose

and then figure out the possible combinations.

i onda otkrijete moguće kombinacije.

Let's look at Mendel's peas, for example.

Pogledajmo Mendelov grašak, na primer.

Let's write the dominant yellow allele as an uppercase "Y"

Zapišimo dominantnu žutu alelu kao veliko "Y"

and the recessive green allele as a lowercase "y."

i recesivnu zelenu alelu kao malo "y".

The uppercase Y always overpowers his lowercase friend,

Veliko Y uvek je jače od manjeg,

so the only time you get green babies

tako da zelene bebe dobijate

is if you have lowercase Y's.

samo ako imate manja slova y.

U Mendelovoj prvoj generaciji,

In Mendel's first generation, the yellow homozygous pea mom

žuta homozigotna majka

će svakom malom grašku dati žutu, dominantnu alelu

will give each pea kid a yellow-dominant allele,

and the green homozygous pea dad will give a green-recessive allele.

a zeleni, homozigotni tata

daće zelenu, recesivnu alelu.

So all the pea kids will be yellow heterozygous.

Tako će sva mala zrna biti žuta i heterozigotna.

Then, in the second generation,

U drugoj generaciji,

kada se uzmu dvoje heterozigotne dece,

where the two heterozygous kids marry,

njihova deca mogu da imaju bilo koji od tri moguća genotipa,

their babies could have any of the three possible genotypes,

prikazujući dva moguća fenotipa

showing the two possible phenotypes

in a three-to-one proportion.

u odnosu tri naspram jedan.

But even peas have a lot of characteristics.

Ali čak i grašak ima dosta karakteristika.

For example, besides being yellow or green,

Na primer, pored zelene i žute boje,

peas may be round or wrinkled.

grašak može biti okrugao ili smežuran,

So we could have all these possible combinations:

pa možemo imati sve ove kombinacije:

round yellow peas, round green peas,

okrugli žuti grašak,

okrugli zeleni grašak,

wrinkled yellow peas, wrinkled green peas.

smežurani žuti grašak

i smežurani zeleni grašak.

To calculate the proportions for each genotype and phenotype,

Da bi se izračunale proporcije svakog genotipa i fenotipa,

we can use a Punnett square too.

može se koristiti Panetov kvadrat.

Naravno, ovo će malo zakomplikovati stvari.

Of course, this will make it a little more complex.

And lots of things are more complicated than peas,

Mnoge stvari su komplikovanije od graška,

like, say, people.

recimo ljudi.

These days, scientists know a lot more about genetics and heredity.

Ovih dana naučnici znaju mnogo više toga

o genetici i naslednosti.

Postoje mnogi drugi načini

And there are many other ways in which some characteristics are inherited.

na koje se nasleđuju neke karakteristike.

Ali sve je počelo sa Mendelom i njegovim graškom.

But, it all started with Mendel and his peas.