BIO1011 Lecture Notes - Lecture 9: Dihybrid Cross, Mendelian Inheritance, Classical Genetics
14 Jun 2018
School
Department
Course
Professor
Lecture 9 - Patterns of Inheritance I
Genetics
● The study of inherited variation to solve biological problems
○ Variation: natural, or induced
Types of genetics
● Transmission level (classical genetics)
○ Looking at a trait and understanding how they’re inherited
● Molecular level genetics
○ How did the DNA encodes a particular protein to achieve a particular
trait
○ Control in the expression of genes
● Population (evolutionary) level genetics
○ Why there are multiple types of a certain characteristic - the purpose of
each characteristic in the population/individual
○ The role in evolution
Autosomal inheritance
● Early theories
○ Selective breeding (farmers had the first theories) led to theories:
■ Pangenesis - charles darwin: genetic information comes from
different parts of the body and then passed down to the children
through the gametes
● Theories that skills were passed down through the
offspring
● Gemmules/pangenes
■ Homunculus - theories that little ‘men’ were in the sperm
■ Blending theory - the blending of the traits between the parents
of the offspring (this relates to the inheritance trees)
● Mendel discovered autosomal inheritance
○ Studied pea plants → this was a very good model organism: had many
progeny, breeded quickly and no one cared about its fate
○ Studied simple traits → led to his success
○ Careful with data and data analysis
Monohybrid crosses - one trait difference at a time
● Filial generation (F1) is the first set of offspring from the parents
● Particulate theory of inheritance (Mendle’s first theory)
● True-breeding when two of the same parents will produce the same plant
every time
○ This theories the identical alleles
○ Dominant alleles were found
○ Each trait has two alleles
Mendel’s laws
Document Summary
The study of inherited variation to solve biological problems. Looking at a trait and understanding how they"re inherited. How did the dna encodes a particular protein to achieve a particular trait. Why there are multiple types of a certain characteristic - the purpose of each characteristic in the population/individual. Selective breeding (farmers had the first theories) led to theories: Pangenesis - charles darwin: genetic information comes from different parts of the body and then passed down to the children through the gametes. Theories that skills were passed down through the offspring. Homunculus - theories that little men" were in the sperm. Blending theory - the blending of the traits between the parents of the offspring (this relates to the inheritance trees) Studied pea plants this was a very good model organism: had many progeny, breeded quickly and no one cared about its fate. Studied simple traits led to his success. Monohybrid crosses - one trait difference at a time.
