Introduction to Molecular Genetics

Life is WHAT

Diverse

1.7 million WHAT species about HOW MUCH of the estimated number on earth

1.7 million EXTANT (living) species about 1/5 of the estimated number on earth

Most species are WHAT about HOW MANY since life first formed

Most species are EXTINCT about 850 million since life first formed

Genetics

Study of HEREDITY and VARIATION in cells, individuals and populations

Gene

Functional unit of heredity and variation 

Genetics is simply the study of WHAT 

Genes

Molecular genetics is WHAT

The study of structure and function of genes at the molecular level (DNA)

Why is studying molecular genetics important

• Human health 

• Forensics 

• Agriculture 

• Environment 

• Evolutionary biology 

Human health

Better understanding of disease results in better drugs and organ matching

Forensics

Crime, paternity test

Agriculture

Superior live stock

Environment

Molecular ecology

Evolutionary biology

Phylogenetics (following one trait in a species) and Phylogenomics (following multiple traits)

Gene

Specific DNA sequence that codes for specific mRNA (and protein) (functional unit of hereditary) 

Genome

All genetic information of an organism (entire DNA sequence) 

Allele

Variant forms of a gene caused by differences in DNA sequence

Genotype

The specific genes inherited by an individual (combination of alleles that you have) 

Phenotype

Visible traits (expression of traits) (has an environmental component)

What is gene expression

• Turning on (expressing) a gene to produce RNA and protein 

• Turning the genotype into a phenotype 

• Follows the central dogma of biology 

Amount of WHAT made varies in a WHAT

Amount of PROTEIN made varies in a POPULATION (the type and abundance in a cell)

Protein expression specifies WHAT

Phenotypes

Although DNA is the information molecule that directs protein expression, WHAT ultimately determine the phenotypes of cells because they are the WHAT

Although DNA is the information molecule that directs protein expression, PROTEINS ultimately determine the phenotypes of cells because they are the TRAITS encoded by the DNA 

What proteins are involved 

• Enzymes 

• Structural proteins 

• Signally (communicating) proteins

Enzymes

Catalyze the synthesis and transformation of all biomolecules

Structural proteins

Maintenance of cell shape

Signally (communicating proteins)

Hormones and receptors

What makes individuals different form one another

1. Different alleles

• Slight variation in gene sequence results in changes in amino acids (eye colour)

2. Different regulation of gene and protein expression (pale blue vs deep blue eyes)

Unique alleles and differential regulations of thousands of genes among individuals leads to WHAT

Unlimited phenotypes possibilities

Individuals that posses similar alleles and genes regulation leads to more similar WHAT

Protein expression in phenotypes (immediate family)

Heredity / Inheritance

The transmission of traits from one generation to the next

A trait is any characteristic of an individual that is WHAT

Heritable

Humans have been studying inheritance for centuries - WHAT in crops and livestock to artificially select for WHAT 

Humans have been studying inheritance for centuries - BREEDING in crops and livestock to artificially select for DESIRABLE TRAITS (size, flavour, seeds etc)  

Gregor Mendel:

• Studied inheritance in WHAT

• Tracked changes in WHAT (and other characteristics) in thousands of pea plants 

• Worked out the mechanism showing how WHAT from one generation could be WHAT to the next - heritable traits result from a mixing of WHAT 

Gregor Mendel:

• Studied inheritance in GARDEN PEAS

• Tracked changes in FLOWER COLOUR (and other characteristics) in thousands of pea plants 

• Worked out the mechanism showing how TRAITS from one generation could be PASSED DOWN to the next - heritable traits result from a mixing of PARTICULATE FACTORS (genes)  

Chromosome theory of inheritance:

• Individuals have HOW MANY copies. of each chromosome 

• Similar (WHAT) chromosomes WHAT during meiosis 

• WHAT : have 1 copy of each chromosome 

• WHAT : Are a random combination of 2 gametes 

Chromosome theory of inheritance:

• Individuals have 2 copies. of each chromosome 

• Similar (HOMOLOGOUS) chromosomes SEPARATE INDEPENDENTLY during meiosis 

• GAMETES : have 1 copy of each chromosome 

• ZYGOTES : Are a random combination of 2 gametes 

Chromosomes are composed of both WHAT and WHAT

Chromosomes are composed of both PROTEINS and DINA

Proteins (WHAT-WHAT%)

• Composed of HOW MANY amino acids 

• Millions of possible WHAT 

• Complex enough to store WHAT 

Proteins (50-60%)

• Composed of 20 amino acids 

• Millions of possible 3D STRUCTURES 

• Complex enough to store HERITABLE INFORMATION  

DNA (WHAT-WHAT%)

• Composed of HOW MANY nucleic acids 

• WHAT and limited WHAT 

• Thought to play a WHAT role 

DNA (40-50%)

• Composed of 4 nucleic acids 

• SIMPLE and limited 3D STRUCTURE 

• Thought to play a STRUCTURAL role