Ch 1
1.1 The birth of genetics
Allele: one of the different forms of a gene that can exist at a single locus
Mendel concluded (1) that genes behave like particles and do not blend together, and
(2) one allele is dominant to the other
Multifactorial hypothesis: a hypothesis that explains quantitative variation by
proposing that traits are controlled by a large number of genes, each with a small
effect on the trait
A and T bound by a double hydrogen bond
G and C are bound by a triple hydrogen bond
Genes have regulatory elements that control gene expression
Genes reside on chromosomes and are made of DNA. Genes encode proteins that
conduct the basic enzymatic work within cells
DNA replication: the process by which a copy of the DNA is produced
Transcription: the process of RNA synthesis form a DNA template
Central dogma: the flow of DNA
1.2 after cracking the code
Model organisms are well suited for genetic studies:
o Small size
o Small genome
o Many offspring
o Short generation time
o Techniques, material, stock available
Genetic discoveries made in model organism are often true of related species and
may even apply to all forms of life
Tools for genetic/genomic analysis
Isolated cellular enzymes: polymerases, nucleases ligases
o Tagging (localizing)
o Cloning
o Modifying (GMO)
o Hybridization (RNA/DNA)
o Amplification
o Genomic computational tools
Transformation: the directed modification of a genome by the external application of
DNA from a cell of different genotype
Progress in genetics has both produced and been catalysed by the development of
molecular and mathematical tools for the analysis of single genes and whole
genomes
1.3 genetics today
The integration of classical genetic and genomics technologies allows the causes of
inherited diseases to be readily identified and appropriate therapies applied
Mutation is a random process that occurs during DNA replication
, Characteristics of DNA (double helix) that make it suitable as carrier of genetic information
Enormous capacity for data storage and diversity: ATGC: gene of 100bp: 4100 possible
unique sequences
Replication: A=T GΞC
Translation into form/function
Stability
Mutability: heritable mutations in genes; alleles -> genetic variation (evolution)
Human genome
80% = “regulatory functional elements”
Enhancers, silencers, insulators, promotors, TADs…
Affected by non-coding RNAs, regulatory proteins, transcription factors…
Many diseases are “complex”
Ch 8
Central to the transfer of information from
DNA to RNA in both bacteria and
eukaryotes are molecular interactions that
involve base pairing of complementary
nucleic acids (DNA and RNA) and biding of
proteins to specific nucleic acid sequences
8.1 RNA structure
mRNA is the information-transfer
intermediary between DNA and protein
RNA has a different chemical composition
than DNA
Uracil can pair with Adenine and Guanine
RNA is single stranded, but pairs to itself to
form stem-loops
Unlike DNA, RNA contains 2’-hydroxyls on the ribose sugars, uracil replaces thymine,
and it is single-stranded but it base pairs to itself from a double stranded region
Four important differences between RNA and DNA:
o RNA has ribose as sugar in its nucleotides (Deoxyribose in DNA) (differ in the
presence or absence of just one oxygen atom at the 2’ carbon)
o RNA is mostly single stranded (DNA is double helix) much more flexible than
DNA
o RNA has Uracil where DNA has Thymine
o RNA can catalyse biological reactions, DNA can not
Stem loops are made up of a double-stranded stem of complementary regions of an
RNA and a single-stranded loop at the end of the stem
See photo in anki Cell bio with the nucleotide nucleoside difference
There are two general classes of RNA’s those wore encode proteins (mRNA) and
those that do not encode proteins (ncRNAs -> tRNA, snRNA)
ncRNAs participate in a variety of cellular processes
o including protein synthesis (tRNA and rRNA),
o RNA processing (snRNA),