Transcript Corn Genetics - Faculty Homepages (homepage.smc.edu)

Biology 22
Genetics and Molecular
Biology
Fall 2007
Biology 22
Fall 2007
• http://homepage.smc.edu/bober_mary
Corn Genetics Laboratory
Outline of Laboratory Discussion
 Introduction to the corn kernel
 Collection of data for use in Chi Square analysis
 Explanation of laboratory exercise
• Collection of data
• Recording of data
Introduction to the Kernel
Variation of colors
Corn Kernel Color
• Color of aleurone masks endosperm color
• Only with colorless aleurone can endosperm
color be determined
• Determined by several genes
Epistasis is a form of gene
interaction in which one gene masks
the phenotypic expression of
another.
Genetic information regarding the corn
color patterns are provided in your lab
manual.
The basis of these patterns.
Aleurone color determined by several genes
(reference lab manual)
• R_
• rr
Purple, Dominant
Colorless aleurone
• C’
• CC or Cc
• cc
Colorless, color inhibitor
Aleurone color in the presence of color alleles
Colorless aleurone layer in presence of R
• P_
• pp
No effect on aleurone layer
Changes color to red
• Y_
• yy
Yellow Dominant
White, Recessive
Explanation of Corn
Genetics Lab Exercise
Today’s lab has 3 crosses of corn
(F2 generation=2nd filial generation)
Note color differneces
• Cross C
• Cross D (darker color is purple)
• Cross F (call purple, may look red!)
•Collection of data:
Count kernels by cross and color
• Select 8 ears from Cross C, D and F
• Count 10 rows per ear
• Grand Total of 240 rows to count!
Direction of a row of kernels
Mark 10 rows
•Record Data
• Record your data at your bench by cross, ear and
color
• After you are finished record your data on the
spreadsheet on the computer in the front of the
lab
• Class data will be on my homepage
• http://www.homepage.smc.edu/bober_mary/
Bring corn to your bench and begin counting!
Ion Exchange Chromatography
Next week lab: Ion Exchange Chromatography
Read 3-25-3-33 in lab manual.