Illustrating Mendelian Genetics: Mr and Mrs Apple-head and their Applettes

IGCSE BIOLOGY GENETICS

Breeding Mr and Mrs Apple-heads to create some Applettes

Yesterday I posted about our Gregor Mendel scientist study.  We finished up our study with a bit of fun, making our own father and mother Apple-heads.  It was a really great way to check the children fully understood the new vocabulary: allele, phenotype, genotype, recessive, dominant, mutation and the like.  The children chose the phenotypes and genotypes for six different features (hair, eyes, nose, ears, tail and mouth).  They married their little Apple-heads, along with a ‘you may now kiss the bride….’

DSC_0449applehead

And we all know what is bound to come from the enthusiastic union between a male Apple-head and a Female Apple-head – yes, little Applettes!

Of course breeding between Apple-heads requires a certain amount of human intervention in order for the union to be productive.  And that is where we came in.  Apple-heads everywhere call us the F1 Gene Bank 😉 (as apposed to a sperm bank).  It is only with the pure genius of the young F1 geneticists (that would be T13, L12, C12 and their very own mum, C(ageless)) that the F1 generation of Applettes can be born.

I’ve included lots of photos so if you want to replicate this you can.  I recommend you read about how we made Mr and Mrs Applehead in the previous post as the formation of the Applettes comes from their genetic make up.

My guys kept saying over and over ‘I can’t believe we get to have so much fun schooling!’  This was a huge success and better than that they really did learn all I had wanted them to learn and were using and understanding all the specific biological vocabulary I had wanted them to master.  Who says you have to learn IGCSE Biology from a book?!

Creating our Applettes

We had kept a record of the parental genotype of the father and the mother for each of the six traits:

DSC_0431applettes

Using these genotypes we crossed the father with the mother for each trait using Punnett squares.  The Punnett squares show the cross between the parents genes and all the possible combination of genes or alleles and the resulting phenotypes.

  • Eyes

The eyes could be either green or yellow, although when we crossed the parents we realised the yellow phenotype would not be seen in the F1 generation.  One hundred percent of the F1 generation would have green eyes due to the dominant I gene being present in every possible eye gene combination from the parents:

DSC_0466appleheadseyes

DSC_0465appletteseye

After the children had given each of their Applettes green eyes they decided to name them.  This simple gift of a name began the process of seeing the Applettes as real living things and over the course of the lesson they began to take on some very human personality traits, as you will soon see….

  • Hair

When we crossed the parents hair genotype we found that 50% of their offspring would have no hair and 50% would have hair:

DSC_0467applette hair

The children could choose which genotype their Applette would have thereby also choosing its phenotype:

DSC_0468appletteshair

Each child jotted down their choices on a white board (photos at the end).

  • Ears

When the parental genotype for ears were crossed we found there was an equal chance of both yellow and pink ears:

DSC_0469Applettesears

The children chose which phenotype and popped it onto their Applette:

DSC_0470applettesears

  • Nose

This time, when the parental genotypes for nose were crossed we found there was a likelihood of only 25% that their off spring would have a brown nose whilst their was a 75% chance it would be yellow:

DSC_0471applettesnose

We had run out of yellow noses so each Applette was given a brown one.  Although statistically this could occur it was far less likely than getting two or more with yellow noses:

DSC_0472applettesnose

We pondered over whether the lack of a gene pool was ever a problem in real life so that people ended up with certain traits because there were not enough genes to make up alternative traits.  Would this be an example of a mutation?  We wouldn’t learn the answer to those questions until we looked at Meiosis and Mitosis in greater detail after Easter, but it sure was fun to discuss!

  • Mouth

It was during the acquisition of its mouth that T13’s Applette, a young male named Ben, began to show his brutish side, shoving the young lady Applettes out of the way in order to be the first to have a mouth.

There was a 50/50 chance of a thin mouth or a wide mouth:

DSC_0473applettemouth

DSC_0474applettesmouth

  • Tail

By the time we were figuring out which tail phenotype to give each Applette, Ben had become almost unbearable, pushing and shoving his way to the front.  We discussed the possibility that maybe he was over compensating for his lack of hair.  After all he was the only bald Applette.  Maybe he felt inferior to his sisters?

Lizzy, of course, didn’t make things easy on him, boasting all the time about what a beautiful Applette she was…

This time there was a 100% chance of getting two tails as opposed to one:

DSC_0475applettestail

I asked what may have happened if one of the Applettes had ended up with only one tail.  L12 thought maybe a mutation, whilst T13 stated that maybe the one tailed Applette had a different father than our Mr Applehead, that Mrs Apple-head had had an affair!  There was a gasp of shock from all the Applettes until I commented that they all had two tails and therefore it was likely that their mummy and daddy were in fact their mummy and daddy!  C12 wondered if I should be teaching them such stuff at such a young age 🙂

As you can see Ben has a new nickname:

DSC_0476applettestail

All our Applettes were now completed.  Some had taken on a personality in the process, all were loved by the F1 geneticists, although not enough to keep them from eating them once the lesson was finished!

T13 and Ben the Bully

Ribbet collagebenthebully2

L12 and Beth the Best

Ribbet collagebenthebully

C12 and Lizzy the Vain

Ribbet collagelizzythevain

The Whole Apple Family

DSC_0484applefamily

This was enormous fun, a really fabulous and hugely successful lesson.  And of course everyone feasted on their family member afterwards!!  Science doesn’t get much more fun than this!

Homeschooling the Middle & High School Years

19 comments

  1. Ha ha ha ha ha, I love it! I always find genetics interesting because of the funny quirks you can get. I still remember reading an article of a very very white family having a biological very very very dark skinned child. It seems several generations back both of the parents had some African blood in them. It was fascinating to read.

  2. Really loved this. I read yesterday’s as well.You made a boring(and confusing at times)subject very fun and interesting. I can’t wait to try this with my kiddo!

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