BIOL 1406 Lecture 13: Biology notes ch. 14

47 views4 pages
8 Feb 2017
School
Department
Course
Professor

For unlimited access to Class Notes, a Class+ subscription is required.

Chapter 14: Mendel and the Gene
Overview: Drawing from the Deck of Genes
Gregor Mendel is considered the father of Genetics
Discovered the basic principles of heredity by breeding garden peas in
carefully planned experiments
Described basic principles of heredity with no knowledge of DNA or the
process of Meiosis
Mendel’s Experimental, Quantitative Approach
Advantages of pea plants for genetic study:
There are many heritable features, or characters (such as flower color);
And character variants (such as purple or white flowers) called traits
Mating of plants can be controlled
Controlled breeding can be achieved by dusting one plant with pollen from
another
Mendel chose to track characters that varied in an either-or manner
Ie. Purple vs. White Flowers
This kept things “simple”
He also used varieties that were true-breeding (plants that produce offspring of the same
variety when they self-pollinate)
In a typical experiment, Mendel mated two contrasting, true-breeding varieties, a process
called hybridization
The true-breeding parents are the P generation
The offspring of the P generation are called the F1 generation
When F1 individuals self-pollinate, the F2 generation is produced
Mendel’s first law: The Law of Segregation
When Mendel crossed contrasting, true-breeding white and purple flowered pea plants, all
of the F1 hybrids were purple
When Mendel crossed the F1 hybrids, many of the F2 plants had purple flowers, but some
had white
Mendel discovered a ratio of about three to one, purple to white flowers, in the F2
generation
Mendel reasoned that only the purple flower factor was affecting flower color in the F1
hybrids
Mendel called the purple flower color a dominant trait and the white flower color a
recessive trait
Mendel observed the same pattern of inheritance in six other pea plant characters
What Mendel called a “heritable factor” is what we now call a gene
Mendel’s Model
Mendel developed a hypothesis to explain the 3:1 inheritance pattern he observed in F2
offspring
Four related concepts make up this model
These concepts can now be explained with what we now know about genes, chromosomes
and meiosis
find more resources at oneclass.com
find more resources at oneclass.com
Unlock document

This preview shows page 1 of the document.
Unlock all 4 pages and 3 million more documents.

Already have an account? Log in

Get access

Grade+
$10 USD/m
Billed $120 USD annually
Homework Help
Class Notes
Textbook Notes
40 Verified Answers
Study Guides
1 Booster Class
Class+
$8 USD/m
Billed $96 USD annually
Homework Help
Class Notes
Textbook Notes
30 Verified Answers
Study Guides
1 Booster Class