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

Translator: Andrea McDonough Reviewer: Bedirhan Cinar

Translator: Marju Männiste Reviewer: Bedirhan Cinar

These days scientists know

Tänapäeval teame,

kuidas tunnused järglastele päranduvad.

how you inherit characteristics from your parents.

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

Sugulastelt ja vanematelt saadud info põhjal

or getting a genetic disease

on võimalik arvutada tõenäosus kindla tunnuse

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

või geneetilise haiguse pärimiseks.

But how is this possible?

Kuidas see võimalik on?

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

Et mõista, kuidas tunnused järglastele päranduvad,

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

peame minema ajas tagasi 19. sajandisse,

and a man named Gregor Mendel.

Gregor Mendeli juurde.

Mendel was an Austrian monk and biologist

Mendel oli Austria munk ja bioloog,

who loved to work with plants.

kellele meeldis tegeleda taimedega.

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

Ta ristas kloostriaias hernetaimi

he discovered the principles that rule heredity.

ja avastas nii pärilikkuse reeglid.

In one of most classic examples,

Mendel ristas puhta kollase- seemnelise sordi taimi

Mendel combined a purebred yellow-seeded plant

with a purebred green-seeded plant,

puhta roheliseseemnelise sordi taimedega

and he got only yellow seeds.

ja sai vaid kollaste seemnetega järglased.

He called the yellow-colored trait the dominant one,

Ta nimetas kollase värvi tunnust dominantseks,

because it was expressed in all the new seeds.

sest see avaldus kõigis uutes seemnetes.

Kui ta ristas uusi kollase- seemnelisi taimi omavahel edasi,

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

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

sai ta nii kollaseid kui ka rohelisi seemneid.

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

Seega oli dominatne kollane rohelise tunnuse alla surunud.

He called this hidden trait the recessive trait.

Ta nimetas sellist allasurutud tunnust retsessiivseks.

Nendest tulemustest järeldas Mendel,

From those results, Mendel inferred

that each trait depends on a pair of factors,

et iga tunnus sõltub kahest tegurist,

one of them coming from the mother

millest üks on saadud emalt

and the other from the father.

ja teine isalt.

Now we know that these factors are called alleles

Nüüdseks teame, et need tegurid on alleelid

and represent the different variations of a gene.

ehk ühe ja sama geeni erinevad variandid.

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

Kui mõlemad alleelid on seemnes ühesugused,

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

on see homosügootne.

Kui alleelid on erinevad,

and what we call a heterozygous pea,

on see seeme heterosügootne.

when the two alleles are different.

This combination of alleles is known as genotype

Alleelide kombinatsiooni nimetatakse genotüübiks

and its result, being yellow or green,

ja selle tulemust, kas kollasust või rohelisust,

is called phenotype.

fenotüübiks.

To clearly visualize how alleles are distributed amongst descendants,

Alleelide jaotumist järglaste seas

on hea ette kujutada Punnetti ruutmeetodiga.

we can a diagram called the Punnett square.

You place the different alleles on both axes

Väljaspool ruudustikku asuvad alleelid,

and then figure out the possible combinations.

ruutude sees aga nende kombinatsioonid.

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

Võtame näiteks Mendeli herned.

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

Kirjutame dominantse kollase alleeli suure tähega Y

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

ja retsessiivse rohelise alleeli väikese tähega y.

The uppercase Y always overpowers his lowercase friend,

Suur täht Y surub alati väikese y alla.

so the only time you get green babies

Seega tekivad rohelised seemned

is if you have lowercase Y's.

vaid kahe väikese y puhul.

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

Esimeses põlvkonnas pärandab homosügootne kollane ema

will give each pea kid a yellow-dominant allele,

igale järglasele dominantse kollase alleeli.

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

Homosügootne roheline isa pärandab retsessiivse rohelise alleeli.

So all the pea kids will be yellow heterozygous.

Seega on kõik järglased heterosügootsed kollased.

Then, in the second generation,

Teises põlvkonnas,

heterosügootsete herneste järglastel,

where the two heterozygous kids marry,

their babies could have any of the three possible genotypes,

võib olla kolm võimalikku genotüüpi

showing the two possible phenotypes

ja avalduda kaks fenotüüpi suhtega 3 : 1.

in a three-to-one proportion.

But even peas have a lot of characteristics.

Aga isegi hernestel on palju tunnuseid.

For example, besides being yellow or green,

Nad võivad olla kollast või rohelist värvi

peas may be round or wrinkled.

ja siledad või krobelised.

So we could have all these possible combinations:

Seega võivad herned olla: siledad kollased, siledad rohelised,

round yellow peas, round green peas,

krobelised kollased või krobelised rohelised.

wrinkled yellow peas, wrinkled green peas.

To calculate the proportions for each genotype and phenotype,

Iga genotüübi ja fenotüübi esinemissageduse arvutamiseks

we can use a Punnett square too.

saame kasutada Punnetti ruutmeetodit.

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

Nüüd on see palju keerulisem

And lots of things are more complicated than peas,

ja on palju asju, mis on hernestest keerulisemad.

like, say, people.

Nagu näiteks inimesed.

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

Täna teame geneetika ja päritavuse kohta palju rohkem.

On veel palju viise, kuidas tunnused päranduvad.

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

Kuid kõik see algas Mendeli ja tema hernestega.

But, it all started with Mendel and his peas.