Lab Manual - eScience Labs

Lab 14: Mendelian Genecs
Concepts to explore:
• Gregor Mendel
• Law of segregaon
• Homozygous
• Heterozygous
• Independent assortment
• Dominant vs. recessive
• Incomplete dominance
• Co-dominance
• Genotype
• Phenotype
• Monohybrid cross
• Dihybrid cross
• Punne square
Introducon
In 1866, Gregor Mendel, an Austrian Monk, published a paper entled “Experiments in plant hybridiza-
on”. It went largely unnoced unl 1900 when it was rediscovered and subsequently became the
basis for what we now refer to as Mendelian Genecs.
Mendel was the first to recognize:
• Inherited characters are determined by specific factors (now recognized these as genes).
• These factors occur in pairs (genes).
When both alleles of a gene are the same they are said to be homozygous, while if they are different
they are said to be heterozygous. When gametes form, these factors segregate so that each gamete
contains only one allele for each gene. Remember, alleles reside on the chromosomes that are dividing.
These original observaons lead to what we now refer to as The law of segregaon and the law of
independent assortment.
Figure 1: Law of Segregaon
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