Study Guide

Update 03/30/2005 08:45 PM

Most of the class did not get this.  I discovered that we had planted seeds to EX 8.2.  We do not have seeds to EX 8.1.  You planted F1 seeds that were generated from parents of these phenotypes:

The seed package was confusing because it said F1, but gave only one (the major) phenotype of each parent and none for the F1.  You will be  studying these plants during the term and writing up a lab report in two parts on them.

Recall that the quiz next week will have general questions from the current lab of the week (or next week's lab) and detailed questions from the previous lab that you completed (under the "This week" section today).  The detailed questions will often be things that you have learned by actually doing the lab, so do not skip sections.  You are expected to be prepared for class by reading the introduction and lab before class.  I realize that the introduction is sometimes fairly lengthy, but quiz questions will come from it as well as the lab.  This Study Guide should help you for the quizzes.

This week
Lab 8.1-8.2:  Mendelian Genetics: Fast Plants
Genetics was first discovered by a monk of the name of Gregor Mendel who had been studying his garden peas.
Peas showed traits were inherited as particle units (genes) rather than by blending
Mendel's model of Inheritance = Mendelian Genetics
Does not explain all inheritance, but is the cornerstone of Genetics

Know these terms:
monohybrid and dihybrid cross, homozygous, heterozygous, dominate gene (or trait), recessive gene, P generation, F1 generation, F2 generation, genotype, phenotype, wild-type trait, mutant trait, hybrid
(most of the terms come from p 187 & 190 of lab manual)

Law of segregation -Mendel observed that allele pairs separate during gamete formation and are reformed as a pair during fertilization.

From Fig 8.1, p 188,
if the G allele codes for green color and the g allele codes for yellow colored peas, then:
 
 

P Generation Green peas (phenotype or appearance)
GG  (genotype or genetic makeup)
Yellow peas (phenotype)
gg  (genotype)
cross GG x gg individuals
this is a monohybrid cross
gametes
G
g
F1 Generation Green peas (phenotype)
Gg (genotype)
cross Gg x Gg individuals
gametes G and g
F2 Generation  
-------- G sperm g sperm
3/4 F2 will be green peas
(GG, Gg, Gg)
1/4 will be yellow
(gg)
G egg
GG
1/4
Gg
1/4
Gg
1/4
gg
1/4
g egg

 

 

Law of independent assortment -the alleles for different traits segregated and assorted themselves independently of other pairs of alleles during meiosis.  For example, the alleles for round or wrinkled peas assort independently of the genes for green or yellow peas.  This independent assortment occurs because either the different genes are on different chromosomes (which assort independently in meiosis) or because the genes are on the same chromosome but are so far apart that a crossing over event occurs making them assort independently.  (At this point in time, I will not hold you to understanding the latter fact.)

 

Figure 8.2 on p 189 of the lab manual explains independent assortment of two traits in a dihybrid cross.

Non-Mendelian Genetics

Studying Wisconsin Fast Plants (Brassica rapa) Figure 8.3 on p 191 shows the life cycle of these plants
In both Ex 8.1 & 8.2, we will begin with F1 seeds (heterozygous for the wild type and mutant genes)
p 192-195 give instructions for planting seeds, pollinating flowers, harvesting and germinating seeds

EX 8.1, Inheritance of Anthocyanin Gene

Your first job is to come up w/ a hypothesis that describes the mode of inheritance of this trait (or gene) Your second job is to come up w/ a prediction for the results of the experiment based on your hypothesis.
You might want to read EX 8.1 before answering it.

You then should dry lab the lab, noting that the lab has:

Today, we will plant F1 seeds (dry lab it).
Please follow the directions on p 196-197.
For example, step #2 on p 197 says to plant the seeds using the procedure on p 193.

EX 8.2:  Inheritance of Plant Color: Green, Yellow-green, and Purple
Ex 8.2 uses plants having four phenotypes:

  1. wild type: green with purple stems/stalks
  2. bright green (no purple)
  3. yellow-green (no purple)
  4. yellow-green with purple stems/stalks
You will be starting with F1 seeds that were from a cross of 2 true-breeding (homozygous) parent lines
parent lines:  bright green (no purple)  and yellow-green w/ purple stems/stalks

Your first job is to come up w/ a hypothesis that describes the mode of inheritance of this trait (or gene)

Your second job is to come up w/ a prediction for the results of the experiment based on your hypothesis. Today
Once again, we will be planting F1 seeds, but different seeds than in Ex 8.1.
Please follow the directions on p 196-197, noting that step #2 says to plant the seeds using the procedure on p 193.

Next week
PGLO Handout:  Molecular Biology

Update 03/30/2005 08:45 PM

Most of the class did not get this.  I discovered that we had planted seeds to EX 8.2.  We do not have seeds to EX 8.1.  You planted F1 seeds that were generated from parents of these phenotypes:

The seed package was confusing because it said F1, but gave only one (the major) phenotype of each parent and none for the F1.  You will be  studying these plants during the term and writing up a lab report in two parts on them.