Help with lesson plan

Next week, I'm teaching genetics and other reptile related subjects to every 7th grade student at a local school. We did this last year and when I talked about recessive, co-dominate and dominate genes, the kids were lost. They talked in terms of little "t" and big "T". However, they did understand me talking about heterozygous and homozygous morphs.

I'm a business major MBA, not a biologist and am a little surprised that the school keeps calling me back to teach something that was not my major. We spend two full days at the school and teach around eight 90 minute classes. I want to do a better job of making it relevant to the kids. Can anyone direct me to a genetics lesson that correlates big T little t to our BP morphs? I've been looking and don't see anything that I can use.

Thanks

Don

Wait... What did they and what didnt they understand...?

Are you doing Punnet squares, with Big T (Tall) and little t (dwarf)?

what is the familiarity the students have with genetics? If you start talking about dominant, co-dominant and recessivge genes to a group of people, mush less kids, that don't have a basic understanding of genetics they they will be lost. I would suggest starting with lots of puctures of simple things such as pea plants to introduce the topic, like a basic biology text would and then progress from there. You can also use examples such as eye color or blood types too. Good luck and let us know how it turns out.

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Originally Posted by GoFride

Are you doing Punnet squares, with Big T (Tall) and little t (dwarf)?

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this. this was how i learned basic genetics in middle school (or maybe high school. don't remember). showing how each parent only passes on one gene. the punnet squares are where i'd start before anything else.

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Originally Posted by Mike41793

Wait... What did they and what didnt they understand...?

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They understood hets and visuals (in our hobby terms). They did not understand recessives, but the teacher stepped in and talked about big T and little t. I'm looking for something to bring all of our terms together so I can say recessive is tT, or whatever it is.

Like I said, I'm a business major and my basic genetics class in school was in the 1970's. I've done a lot of self study's since then, but I learned scientific terms, not little letter big letter. I'm just trying to reconcile the terms so the lesson plan has meaning for them. I understand what I'm doing in my breeding program, just need to translate to their terms.

a recessive would be tt

Het x Het would be:
Tt x Tt and result in:
25%TT (normal)
50% Tt (hets)
25% tt (visual recessives)

Is that what you mean...?

Imo itd be easier to use Nn x Nn for normals. Idk where the Tt came from lol

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Originally Posted by creepin

this. this was how i learned basic genetics in middle school (or maybe high school. don't remember). showing how each parent only passes on one gene. the punnet squares are where i'd start before anything else.

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Yup, that is what I'm trying to get to. How does the letters relate to recessive, dominate and co-dominate genes.

Guys, I'm over 50 years old and like I said, my last formal lesson in genetics was in the 70's. I can put together the odds for double recessives and many combos of BP genes, but can't translate it to big and little letters.

If they understand "big T" and "little t", use a punnet square when talking about the recessives. For albinos, for example, show them this table:

PARENTS (albino x het albino)	a	a
A	Aa - het albino	Aa - het albino
a	aa - albino	aa - albino

You can obviously change up the genetics to do something with pieds.

As for the actual letters, they are interchangeable. You usually use a letter that's in the genes you want to work with. So for albinos, you use the letter "a". For pieds, you might use the letter "p". Just use letters where the upper and lower case look different from each other. Don't use something like Cc or Ss. It can get confusing if you are manually writing it out.

The upper case letters represents the non-recessive gene or the "wildtype" gene. The lower case letter represents anything recessive.

Not sure if this will help?

http://www.arbreptiles.com/genetics101.shtml

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Originally Posted by Mike41793

a recessive would be tt

Het x Het would be:
Tt x Tt and result in:
25%TT (normal)
50% Tt (hets)
25% tt (visual recessives)

Is that what you mean...?

Imo itd be easier to use Nn x Nn for normals. Idk where the Tt came from lol

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Yup, that is what I'm looking for. That would be recessive heterozygous pairings (i.e. Pied het pairing). Where can I find the same thing for all of the alleles?

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Originally Posted by Don

Yup, that is what I'm looking for. That would be recessive heterozygous pairings (i.e. Pied het pairing). Where can I find the same thing for all of the alleles?

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The link tlich posted shows examples of all of them. I wont bother typing them out lol^

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Originally Posted by tlich

Not sure if this will help?

http://www.arbreptiles.com/genetics101.shtml

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PERFECT! Thanks. This will help me translate.

There is no set letter that corresponds to a gene. You can pick any letter you want! Most people use "a" for albino, "p" for pied, "c" for clown, "x" for axanthic, etc. However, just be cautious of using "S", "C", and "X" because it's hard to distinguish upper from lower case if you aren't careful.

Oh and after googling i remembered that he most likely used T's bc usually punnett squares are taught using gregor mendels pea plants as an example. Tt= tall plant, tt=short plant

In case you cared lol.

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Originally Posted by Mike41793

Oh and after googling i remembered that he most likely used T's bc usually punnett squares are taught using gregor mendels pea plants as an example. Tt= tall plant, tt=short plant

In case you cared lol.

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Mike, that is correct. The teacher emailed me today to tell me they had run through the pea plants genetics and that explains why she used the letter T.

God, I feel old. However, never too old to learn something new! And, yes I do care. The coolest thing that has happened to me since breeding balls is several Facebook messages and a few posts from former students who went through our class.

This year will be especially cool as we are bringing an Eastern Indigo (to help talk about conservation) and a blue tongue skink and Beardie. Hopefully, the two days worth of work will help educate a bunch of kids that reptiles are not to be feared.

This is late, but it may be useful in the future if not now.

Some freely downloadable sources for genetics information:
No-frills genetics guide. This is a sticky in the Boa Genetics forum at http://http://www.redtailboas.com/f1...s-guide-53782/. The definitions use a minimum of jargon. They are mostly paraphrases of the definitions in King and Stansfield's A Dictionary of Genetics.

Project on Genetics. See the Contents page at http://www.ringneckdove.com

A Survey of Genetics (4 parts), by Wilmer Miller. See the Contents page at http://www.ringneckdove.com (This book has a page on appropriate gene symbols.)

Mendelism, by R. C. Punnett. http://www.gutenberg.org/ebooks/28775. Printed in 1911 so much of the text is badly out of date. But the pictures are still useful, and they are out of copyright, with no restrictions on their use.

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Before studying genetics, a student should have a grounding in cell division, both mitosis and meiosis. Meiosis explains how a baby gets one member of each gene pair from each parent.

A smart student may ask why humans, mice, and other organisms have thousands of genes, but there is only one gene pair in that Tt example. The scientific method advises using one variable in an experiment and holding everything else constant. But there is no way to breed an organism without having all those other genes present. Geneticists can ignore all but one pair of genes if they make two assumptions:
1. Each gene pair in the parental male and female is homozygous.
2. The parental male and female are genetically identical except in one gene pair.

These two assumptions can trip us up if there are two pairs of mutant genes in a mating when we think there is only one. This is especially true when the effect of one pair of genes masks the effect of the genes in the other pair. And the results of two different genetics studies are difficult to combine unless a stock in one study is the same as a stock in the second study.

To avoid these problems, mouse and fruit fly geneticists use wild type (AKA normal) as the standard. The wild type phenotype is the most common phenotype in the wild population. (In the wild house mouse, the wild type coloration is a brownish color called agouti.) A wild type gene is the most common gene at a given location in the chromosomes in the wild population.

Using wild type simplifies the above assumptions to the following:
1. Each unspecified gene pair in the parental male and female is homozygous wild type.
2. One gene pair in one parent is specified as homozygous mutant.

Those assumptions are technically incorrect in the real world. But they work out in practice because phenotypes act like assemblages of independent characters. The gene that causes albino fur in mice does not affect blood type, and the blood type genes do not affect fur color (or lack of color).

The biochemists say that one gene does not produce what we see as coloration. One mutant gene can change the color or even prevent its formation. But that does not mean that the corresponding normal gene produces the normal coloration by itself. Color production is more like an assembly line with many stations. Many genes provide directions to the assembly line, with each gene telling one or a few stations what to do. Each gene corresponds to one line in the operating procedure book. We look at what rolls off the end of the line. If what comes off is what was expected (normal), then all the machines are getting the standard line from the OP. If something unexpected comes off, there is a typo in least one line. That typo is making the machinery malfunction -- either to do nothing or to do something unexpected.

As there are pairs of genes, there are two copies for each line in the operating procedure. Those may be two copies of the standard line, one copy of the standard line and one with a typo, two copies with the same typo, or two with different typos. Using breeding tests, we can figure out a number of things. Does the malfunction come from a typo in one line in the OP book or in more than one? Do two malfunctions come from different typos in the same line or from typos in two different lines? Are two lines close together in the book? Etc.