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Looking Glass Genetics : Gene Mapping

The Mad Hatter and March Hair setting up a breeding experiment in a teacup

The Mad Hatter and March Hair setting up a breeding experiment in a teapot

In addition to Genetic Counseling for the cards, your lab has been investigating the genetics of the Dormouse.

Dormice have either the ability to Speak (S) – or are Mute(s).

Additionally, they are either Cruel or Kind.

You wish to map the distance between the Speech and Disposition genes and determine whether Cruelty or Kindness is dominant. (Here, not a metaphysical question)

You begin by obtaining true-breeding animals:

  1. A Speaking , Kind Male
  2. A Mute, Cruel Female

(oh, the cries of misogyny!)

Once bred, this coupling gives rise to a litter of six offspring. All six can speak and are unfailingly kind.

These offspring are then bred to true-breeding homozygous recessive mates. The results of these matings are:

      #                     Phenotype

35                   Speaking, Kind

15                   Speaking, Cruel

15                   Mute, Kind

35                   Mute, Cruel

  1. What can you determine from these results?

In similar experiments, Cruel, Longhair and Kind,Shorthair animals were examined. Both parentals were true breeding and the F1 litter consistend entirely of Kind, Longhair animals. These F1 were then crossed with homoztgous recessives for both traits, resulting in:

    #                     Phenotype

20                   Kind, Longhair

80                   Kind, Shorthair

80                   Cruel, Longhair

20                   Cruel, Shorthair

What do these data add to your understanding of Dormouse genetics? Can you map the three genes to one Chromosome? What experiment do you want to do next?

 
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Posted by on November 8, 2014 in Uncategorized

 

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A suggestion and a request

As you can see from my previous post, my general bio class has been delving into the molecular mechanisms of replication, transcription and translation. All of these processes were worked out in the latter half of the 20th century following the publication of DNA’s structure by Watson and Crick. Because Watson and Crick’s work was so seminal, it seems reasonable for me to make a couple of book recommendations relating to that work. ImageThe first is The Cartoon Guide to Genetics.  With a title including the word ‘cartoon’, it is tempting to dismiss this book, but you would be doing yourself a disservice. This is one of the most clearly written genetics books you can ask for. Despite the apparent simplicity, it is surprisingly thorough. I am presently considering making this book required reading for a genetics / ecology course I am planning.

Another book is James Watson’s The Double Helix. This book is short and an easy read, yet it puts you right in the center of the Imageaction – both scientific and personal – that surrounded the elucidation of this molecule’s structure.

This brings me to my request… As I mentioned above, I am working on a new course which will act as a second semester to my current general bio class. The main topics of this class will be inheritance, population genetics, the dynamics of populations and how all this informs our knowledge of evolution. I have a couple ideas already, but I thought I would open this space up to accept any suggestions the peanut gallery may have. If you have a book that you like that was a good read and brought up some interesting conversations, let me know and I’ll check it out.

 
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Posted by on April 30, 2013 in Uncategorized

 

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Reflecting on Inheritance

Last semester I posted an essay introducing inheritance, the idea of factors/alleles, how alleles are distributed into sex cells that combine with other sex cells to bring about a new generation. Looking back on this post, I think it would be a good idea to point to it from here and suggest that all my General Biology students read through it to ensure that they understand the basics of inheritance before we go on.

Image

Wormhole to an old post

You can go directly to that post here or drop through the wormhole on the right.

 
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Posted by on March 27, 2013 in Uncategorized

 

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