Genetics basics Quick Tutoring Session

Genetics Vocab and Basic Punnet Squares

This is PART 1 of the tutoring that goes with BOTH of the Unit 7 tests. You should really attend both sessions if you want to be fully ready.

Match

Match the following

• gene

• allele

• heredity

A section of DNA coding for a trait

One of many different versions of DNA

Passing of traits from parents to child

• A section of DNA coding for a trait

• One of many different versions of DNA

• Passing of traits from parents to child

Match

Match the following

• Heterozygous

• Homozygous

• Dominant

• recessive

Two different alleles like Aa, Dd or RW

Two of the same alleles, like AA or bb

A trait always shows up

A trait only shows up when alone

• Two different alleles like Aa, Dd or RW

• Two of the same alleles, like AA or bb

• A trait always shows up

• A trait only shows up when alone

This is the physical traits of an individual.

This is normally just a description like 'Dog with yellow fur.'

Phenotype

This is the exact alleles (Letters) and individual has.

Either shown as letters like Aa
Or
Described with words like 'Homozygous Recessive.

Genotype

Some more big terms...

Here's a sample problem. We're going to do it in 5 steps

The Problem:

Yellow fur is dominant to Black fur in domestic dogs. If a Heterozygous Yellow dog is crossed with a Black dog, what are the chances that the offspring will end up being black dogs?

1st, find information about inheritance and parents.

I've bolded the dominance and underlined parents.

Yellow fur is dominant to Black fur in domestic dogs. If a Heterozygous Yellow dog is crossed with a Black dog, what are the chances that the offspring will end up being black dogs?

2nd, Make a key.

My key is going to have all possible combos of alleles.

Yellow fur is dominant to Black fur in domestic dogs. If a Heterozygous Yellow dog is crossed with a Black dog, what are the chances that the offspring will end up being black dogs?

F = Yellow
f = black

FF = Yellow (Homozygous)
Ff = Yellow (Heterozygous)
ff = black (homozygous)

Drag and Drop

3rd, write out the cross!

Yellow fur is dominant to Black fur in domestic dogs. If a Heterozygous Yellow dog is crossed with a Black dog, what are the chances that the offspring will end up being black dogs?

Placeholder

x ​

Placeholder

Drag these tiles and drop them in the correct blank above

Ff

ff

FF

4th, Set up and fill in your square.

I'm keeping my key handy!

Crossing Ff x ff

F = Yellow
f = black

FF = Yellow (Homozygous)
Ff = Yellow (Heterozygous)
ff = black (homozygous)

F f

f Ff




f

Draw

Fill in the rest of the Punnet square!

(Draw!)

Finally, use your square for ratios and answer the question!

I'm keeping my key handy!

Crossing Ff x ff

F = Yellow
f = black

FF = Yellow (Homozygous)
Ff = Yellow (Heterozygous)
ff = black (homozygous)

F f

f Ff ff


f Ff ff

Phenotype:
There are 2 Yellow and 2 Black
That's a 2:2 ratio, or
50%:50% percent ratio.

Genotype:
There are two Ff and two ff
That's also 2:2 or 50%:50%

Match

Match the following

• Purebred

• Hybrid

• Heterozygous Dominant

• Homozygous Recessive

• Homozygous Dominant

Homozygous

Heterozygous

Aa

bb

CC

• Homozygous

• Heterozygous

• Aa

• bb

• CC

Fill in the Blank

In this Punnet square, what PERCENT are going to be homozygous recessive

Labelling

Drag and drop the labels where they go (You will only use four!)

Drag labels to their correct position on the image

aa

aa

AA

Aa

AA

Aa