Question

In a monohybrid cross, if the gene for tall (T) plants was incompletely dominant over the gene for short (t) plants, what would be the predicted result of crossing two intermediate (Tt) parent plants? (Hint: You may want to complete a Punnett square.)

25 percent tall, 50 percent intermediate, 25 percent short

50 percent tall, 25 percent intermediate, 25 percent short

100 percent intermediate

25 percent tall, 75 percent intermediate

thankssss! <3

Answer 1

You know how to make a punnett square?

Answer 2

No I don't. D:

Answer 3

Okay. Well I can teach you everything you need to know, in order to solve this problem.

You ready to work with me?

Answer 4

Yeah! Sure. (:

Answer 5

First of all, we need to know about ALLELES.

ALLELES are the letters that stand for certain traits.

If we look at the problem,
we can see two different alleles:

( T ) and ( t ).

( T ) is tall.
And ( t ) is short.

Answer 6

Again, there are two different alleles here.

T....and....t.

You follow so far?

Answer 7

Yeah. There's a "Tall" allele and a "short" allele

Answer 8

Okay.

Now, we need to know about GENOTYPES.

This problem is talking about plants.

Every plant has a GENOTYPE, made of TWO ALLELES.


Here are some examples of genotypes:

(T T)

(T t)

(t t)

Answer 9

And both plant "parents" share the same allele combo

Answer 10

Yes,
in this problem, both of the parents have the same GENOTYPE (allele combo).

Answer 11

The problem tells us that both parents have the genotype (T t).

Answer 12

Okay.

So, in this problem, the GENOTYPE tells us how tall the plants will be.

Answer 13

Again, let's look at the ALLELES.

( T ) is tall.
( t ) is short.

**Here's a very BIG RULE:
In most genotypes, the CAPITAL alleles matter more than the lowercase alleles.

Answer 14

So let's pretend that the plant has the genotype (T T).

The plant will be TALL.
Because it has two Capital T's.

Answer 15

Now, let's pretend that the plant has the genotype (t t).

(t t).

There are no capital letters here.

So, the plant will be SHORT.

------------

Are you alright so far?

Answer 16

Yeah! I'm following.

Answer 17

Okay. Sorry, the site decided to freeze on me.

Answer 18

So,

remember the Big Rule?
Capital alleles matter more than lowercase alleles.

What would happen of the plant had the genotype (T t) ??

Well...NORMALLY....the plant would be TALL.
Because there's a Capital T there.
See?

Answer 19

But this problem is liiiittle different.

In this problem.....the capital T is "incompletely dominant."

Here's what that means:

If a plant has the genotype (T t),
then it won't be tall.
It will actually have MEDIUM height.

Answer 20

Ooooh. Since it's like, a mix between short and tall and it equals out to medium? Okay, yeah, I get that.

Answer 21

Yes! Exactly.

Answer 22

So now quick genotype review:

(T T) would be TALL.

(T t) would be MEDIUM.

(t t) would be SHORT.

Answer 23

Now let's make Punnett Squares.

Let's see....both parents are (T t), right?

Let me show you how that would look on a Punnett Square.