Wednesday, October 6, 2010

Mendel and His Peas


Pictured above is the father of modern genetics: Gregor Johann Mendel.  He was born in 1822 in what is today the Czech Republic.  He was the son of a farmer that due to financial issues joined a monastery so that his pursuit of math and science would be paid for in full.

Interestingly enough he wanted to be a teacher but after several failed attempts to pass his teaching certification exam, he resorted to a life a research and eventually became head of the monastery.

Over a 7 year course of time (1860s), he bred around 30,000 pea plants keeping detailed observations of their lineage while he tracked traits such as flower color and plant height. 

Unfortunately, his attempts to publish his works were not received well and it wasn't until he died that his experiments were recognized for their attention to detail and proof of genetic inheritance.

Review Mendel's pea plant experiments by following the hyperlink and go through the animation.

His laws are the basis for current genetic theory and research:

1. Law of segregation
    Think back to meiosis.  Remember that of each pair of chromosomes (DNA) separates in anaphase II so  
    each gamete only has 1/2 of alleles.  For example, if your normal body cells have a dominant and  
    recessive allele for a particular trait, then each of your gametes will have either a dominant or a recessive 
    allele for that trait because the pairs separate in the final stages of meiosis.

     Click this link for a review of meiosis and be sure to follow the chromatids on their journey to see how 
     the pair of gametes are split from their homolog in the final stages.

2. Law of Independent Assortment  (Click the title for a review animation)
     Genes located on separate chromosomes are inherited without relying on one another.  Much like 2 cars 
     driving down the highway are able to make turns without prompting the other vehicle to follow suit.


Mendel put into works what may have taken scientists far longer to have discovered in present day.  Read the next blog to hear about Sir Reginald Punnett and his miraculous tool to predict how offspring will inherit their traits.



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