Genetics 214
INTRODUCTION TO GENETICS - study unit 1
▪ Genetics: study of how genes bring about traits in living things/how it is inherited
and how biological information is stored, transmitted, translated and expressed
▪ Genes: specific sequences of nucleotides that code for a particular protein
▪ Genes transmitted between generations through meiosis and sexual reproduction
▪ As data grows, scientists access more information through age of information and big
data. Researchers look at larger data sets, deeply analyse them and identify
unobserved new patterns
▪ Large data sets enables new correlations to understand genetic code and complexity
▪ Big data in genetics opens new possibilities for research and treatment:
o Makes it easier to identify potential therapies for genetic diseases faster
o Researchers can develop sophisticated algorithms to identify genetic variants
previously missed therefore identification of potential treatments/therapies
o Drives development of new technologies (gene editing and gene therapy) to
treat rare genetic diseases
▪ Data sets get larger and more complex = data misused or misinterpreted
▪ Big data used ethically, privacy not compromised and weary about collected data
What genetics is
▪ Field of biology studying the structure and function of genes, genetic variation and
heredity in organisms
Science of inheritance & differences between individuals, populations and species
▪ Genetic branches provide mechanisms that control heredity between generations
▪ Classical genetics branch = study of Mendelian inheritance and transmission of genes
from parents to offspring in discrete traits
▪ Molecular genetics branch = studies the structure, function & regulation of DNA, RNA
and proteins (used for understanding gene & expression for processes)
▪ Population genetics branch = studies the changes in gene frequencies in a population
over time & utilises the effects of natural selection of gene frequencies
▪ Evolutionary genetics branch = studies the patterns of genetic variation &
evolutionary change in populations over time
▪ Comparative genetics branch = compares the genetics of closely related species &
used to understand evolutionary processes shaping genomes of different species and
inform knowledge of their development
▪ Developmental genetics branch = genetic basis of development, creation of single
cell embryo to complex organs
History of genetics
Neolithic revolution = shift in way humans lived & interacted with environment/each other allowing
for development of complex societies & cultures. Began around 12 000 BCS in middle East
▪ Beginning of agriculture & animal domestication
▪ Foundation for advancement of human society allowing for development of civilisations
(Ancient Egypt & Mesopotamia)
, Genetics 214
▪ First permanent villages & emergence of social complexity
▪ Development of agriculture changed = eating habits, interactions with environment &
organised societies
▪ Humans produced food in abundance allowing settlement into permanent villages instead of
being nomadic = emergence of social complexity, power & class
▪ Domesticated animals for transportation, source of energy & entertainment
Ancient Greek philosophy = spontaneous generation. Began around 500 BC
▪ Golden age of Greek culture = difference between living organisms notes & explained in
spontaneous generation
▪ Spontaneous generation = belief that living organisms arose from non-living matter
▪ Aristotle challenged = living things arose from other living things based on Hippocrates
teachings
▪ Hippocrates = active humors in parts of the body served as bearers of hereditary traits
passed onto offspring
Humors are healthy or diseased. Diseased = appearance of new-borns with congenital
disorders/deformities
Humors altered in individuals before passed onto offspring explaining how new-borns inherit
traits that parents has acquired in response to environment
▪ Aristotle = male semen contained vital heat with capacity to produce offspring of the same
form as the parent, heat cooked & shaped menstrual blood produced by female (physical
substance giving rise to offspring). Sperm contained on Homunculus
▪ IN SIGHT INTO PRINCIPLES OF HEREDITY & VARATION
17th - 19th century
▪ Theory of epigenesis (Willian Harvey 1600s) refutes theory of preformation
Epigenesis: organism develops from fertilised egg by succession of developmental events
that transforms the egg into an adult
Preformation: germ cells of each organism contains preformed miniature adults
(homunculus) that unfolded during development
18th century: blending inheritance Lamarck, Charles Darwin & Gregor Mendel
Lamarck = organism capable of transmitting acquired traits to offspring. Darwin & Mendel =
traits inherited from combination of existing traits (not a process of blending)
▪ Cell theory proposed (Schwann): all organisms are composed for basic structural
united called cells derived from pre-existing cells
▪ Spontaneous generation disproved: cell theory & Louis Pasteur disproved
spontaneous generation (Greek philosophers)
▪ Gregor Mendel’s (Australian monk) postulates
Pea plants laid foundation of heredity: traits were inherited through discrete units (genes)
Introduced concept of genes (building blocks of heredity)
▪ Darwin’s theory of natural selection (independent; unknown of Mendel’s work)
, Genetics 214
Origin of species by Charles Darwin: explanation of mechanisms of evolutionary change but
lacked understanding of genetic basis of variation & inheritance
Therefore theory open to reasonable criticism in 20th century
Heredity & development were dependant on genetic information residing in genes
contained in chromosomes contributing to each individual by gametes= chromosome theory
Chromosomal theory of inheritance: Walter Sutton 1902
▪ Chromosomes are the carriers of genetic material & genetic factors are located on
loci on chromosomes
▪ Transmission of traits from parent to offspring due to transfer of chromosomes
between generations
▪ Diploid number (2n): each species has a set number of chromosomes
Humans diploid number = 46 chromosomes comprised of 23 homologous pairs (n)
▪ Chromosome exists in pairs as homologous chromosomes
▪ Chromosomes undergo meiosis & mitosis
Segregation and exchange of chromosomes (crossing over) between the 2 sets of
chromosomes in a parent cells
Meiosis halves the chromosome number so that each gametes (egg/sperm cell)
receives 1 copy of each chromosomes = haploid (n) genetic information passed
between generations. Mitosis duplicates the chromosomes = 2n
▪ Mutations located on chromosomes responsible for differences between individuals
leading to variation
Chromosomal rearrangements: translocations & inversions show how mutations
affect gene expression = variation
▪ Provides insight into molecular basis of genetic variation for genetic research
Genetic variation
▪ Mutation in genes located on chromosomes = new versions of genes (alleles)
creating different individuals
▪ Mutation: any heritable change in DNA sequence & source of all genetic variation
Inheritance of traits in fruit fly: white-eye variant is an allele of the white gene vs red-
eyes allele in Drosophila
▪ Mutant genes used as markers & geneticist map locations of genes on chromosomes
▪ Alleles: alternative forms of a gene that produce differences in observed phenotypes
Genotype is the set of alleles for a given trait carried by an organism
▪ Different alleles = different phenotypes of traits
▪ Homologous copies of alleles at a locus = genotype
▪ Dominant allele = dominant phenotype if homozygous recessive or heterozygous
▪ Recessive allele = recessive phenotype if homozygous recessive
Chemical nature of heredity
Dawn of molecular genetics
▪ DNA carries genetic information & information stored = phenotype
, Genetics 214
▪ Watson & Crick were awarded the Nobel Prize in 1962 for the structure of DNA
▪ Nucleotides: sugar group, phosphate group and a base (A, T, G & C)
▪ Nitrogenous bases attach to sugars of DNA strands which attaches to a phosphate
group in a double helix ring shaped molecules
▪ Adenine (A) pairs with thymine (T) & guanine (G) pairs with cytosine (C) in DNA.
Adenine pairs with uracil (U) in RNA
▪ Sugar-phosphate backbone: DNA is a polymer made of nucleotide units
▪ DNA strands held together by hydrogen bonds between bases on adjacent strands
Replication errors cause mutations = new variations
▪ DNA: chemical name for the long, stringy chromosomes inside of cells
▪ Genes: segments of DNA coding for proteins
▪ Alleles: different version of the same gene with small differences in their nucleotide
sequences
Central dogma: how genes create phenotypes from DNA to proteins
▪ DNA sequence - transcription - mRNA sequence (amino acid coded in 3 codons
identical to coding strand with a U base not T base) - translation - protein
▪ Bases on a single strand act as a code
▪ 3 letter codons form coding for amino acids (building blocks of proteins)
▪ DNA stores information to run the cell
▪ RNA polymerase enzyme transcribes DNA into mRNA (messenger ribonucleic acid)
▪ mRNA splits apart the 2 strands that form the double helix & reads the template
strand copying the sequence of nucleotides from the coding strand
▪ Only difference between the mRNA and original DNA is that uracil (U) with a similar
structure replaces thymine (T). All the other bases remain the same
▪ mRNA carries genetic code out of the cell nucleus to the cytoplasm where protein
synthesis occurs
▪ Translation process turns the mRNAs code into proteins
▪ Ribosomes carry out the process building up proteins from the amino acids coded for
▪ Proteins perform the functions in the cells
Modern evolutionary synthesis
▪ Rediscovery of Mendel’s work
▪ Amalgamation of Mendelian & Darwinian principles
▪ Origin of population & quantitative genetics
Quantitative genomics: study of genetic basis of variation in quantitative traits
Combines traditional tools of genetics & molecular biology with modern statistics &
computer science to understand underlying genetic architecture of phenotypic variation
Used to study population structure of no. species (humans, plants and animals) = insight in
relationships between populations, genetic structure & investigate genetic basis of traits
(foraging behaviour, growth rate and disease resistance)
INTRODUCTION TO GENETICS - study unit 1
▪ Genetics: study of how genes bring about traits in living things/how it is inherited
and how biological information is stored, transmitted, translated and expressed
▪ Genes: specific sequences of nucleotides that code for a particular protein
▪ Genes transmitted between generations through meiosis and sexual reproduction
▪ As data grows, scientists access more information through age of information and big
data. Researchers look at larger data sets, deeply analyse them and identify
unobserved new patterns
▪ Large data sets enables new correlations to understand genetic code and complexity
▪ Big data in genetics opens new possibilities for research and treatment:
o Makes it easier to identify potential therapies for genetic diseases faster
o Researchers can develop sophisticated algorithms to identify genetic variants
previously missed therefore identification of potential treatments/therapies
o Drives development of new technologies (gene editing and gene therapy) to
treat rare genetic diseases
▪ Data sets get larger and more complex = data misused or misinterpreted
▪ Big data used ethically, privacy not compromised and weary about collected data
What genetics is
▪ Field of biology studying the structure and function of genes, genetic variation and
heredity in organisms
Science of inheritance & differences between individuals, populations and species
▪ Genetic branches provide mechanisms that control heredity between generations
▪ Classical genetics branch = study of Mendelian inheritance and transmission of genes
from parents to offspring in discrete traits
▪ Molecular genetics branch = studies the structure, function & regulation of DNA, RNA
and proteins (used for understanding gene & expression for processes)
▪ Population genetics branch = studies the changes in gene frequencies in a population
over time & utilises the effects of natural selection of gene frequencies
▪ Evolutionary genetics branch = studies the patterns of genetic variation &
evolutionary change in populations over time
▪ Comparative genetics branch = compares the genetics of closely related species &
used to understand evolutionary processes shaping genomes of different species and
inform knowledge of their development
▪ Developmental genetics branch = genetic basis of development, creation of single
cell embryo to complex organs
History of genetics
Neolithic revolution = shift in way humans lived & interacted with environment/each other allowing
for development of complex societies & cultures. Began around 12 000 BCS in middle East
▪ Beginning of agriculture & animal domestication
▪ Foundation for advancement of human society allowing for development of civilisations
(Ancient Egypt & Mesopotamia)
, Genetics 214
▪ First permanent villages & emergence of social complexity
▪ Development of agriculture changed = eating habits, interactions with environment &
organised societies
▪ Humans produced food in abundance allowing settlement into permanent villages instead of
being nomadic = emergence of social complexity, power & class
▪ Domesticated animals for transportation, source of energy & entertainment
Ancient Greek philosophy = spontaneous generation. Began around 500 BC
▪ Golden age of Greek culture = difference between living organisms notes & explained in
spontaneous generation
▪ Spontaneous generation = belief that living organisms arose from non-living matter
▪ Aristotle challenged = living things arose from other living things based on Hippocrates
teachings
▪ Hippocrates = active humors in parts of the body served as bearers of hereditary traits
passed onto offspring
Humors are healthy or diseased. Diseased = appearance of new-borns with congenital
disorders/deformities
Humors altered in individuals before passed onto offspring explaining how new-borns inherit
traits that parents has acquired in response to environment
▪ Aristotle = male semen contained vital heat with capacity to produce offspring of the same
form as the parent, heat cooked & shaped menstrual blood produced by female (physical
substance giving rise to offspring). Sperm contained on Homunculus
▪ IN SIGHT INTO PRINCIPLES OF HEREDITY & VARATION
17th - 19th century
▪ Theory of epigenesis (Willian Harvey 1600s) refutes theory of preformation
Epigenesis: organism develops from fertilised egg by succession of developmental events
that transforms the egg into an adult
Preformation: germ cells of each organism contains preformed miniature adults
(homunculus) that unfolded during development
18th century: blending inheritance Lamarck, Charles Darwin & Gregor Mendel
Lamarck = organism capable of transmitting acquired traits to offspring. Darwin & Mendel =
traits inherited from combination of existing traits (not a process of blending)
▪ Cell theory proposed (Schwann): all organisms are composed for basic structural
united called cells derived from pre-existing cells
▪ Spontaneous generation disproved: cell theory & Louis Pasteur disproved
spontaneous generation (Greek philosophers)
▪ Gregor Mendel’s (Australian monk) postulates
Pea plants laid foundation of heredity: traits were inherited through discrete units (genes)
Introduced concept of genes (building blocks of heredity)
▪ Darwin’s theory of natural selection (independent; unknown of Mendel’s work)
, Genetics 214
Origin of species by Charles Darwin: explanation of mechanisms of evolutionary change but
lacked understanding of genetic basis of variation & inheritance
Therefore theory open to reasonable criticism in 20th century
Heredity & development were dependant on genetic information residing in genes
contained in chromosomes contributing to each individual by gametes= chromosome theory
Chromosomal theory of inheritance: Walter Sutton 1902
▪ Chromosomes are the carriers of genetic material & genetic factors are located on
loci on chromosomes
▪ Transmission of traits from parent to offspring due to transfer of chromosomes
between generations
▪ Diploid number (2n): each species has a set number of chromosomes
Humans diploid number = 46 chromosomes comprised of 23 homologous pairs (n)
▪ Chromosome exists in pairs as homologous chromosomes
▪ Chromosomes undergo meiosis & mitosis
Segregation and exchange of chromosomes (crossing over) between the 2 sets of
chromosomes in a parent cells
Meiosis halves the chromosome number so that each gametes (egg/sperm cell)
receives 1 copy of each chromosomes = haploid (n) genetic information passed
between generations. Mitosis duplicates the chromosomes = 2n
▪ Mutations located on chromosomes responsible for differences between individuals
leading to variation
Chromosomal rearrangements: translocations & inversions show how mutations
affect gene expression = variation
▪ Provides insight into molecular basis of genetic variation for genetic research
Genetic variation
▪ Mutation in genes located on chromosomes = new versions of genes (alleles)
creating different individuals
▪ Mutation: any heritable change in DNA sequence & source of all genetic variation
Inheritance of traits in fruit fly: white-eye variant is an allele of the white gene vs red-
eyes allele in Drosophila
▪ Mutant genes used as markers & geneticist map locations of genes on chromosomes
▪ Alleles: alternative forms of a gene that produce differences in observed phenotypes
Genotype is the set of alleles for a given trait carried by an organism
▪ Different alleles = different phenotypes of traits
▪ Homologous copies of alleles at a locus = genotype
▪ Dominant allele = dominant phenotype if homozygous recessive or heterozygous
▪ Recessive allele = recessive phenotype if homozygous recessive
Chemical nature of heredity
Dawn of molecular genetics
▪ DNA carries genetic information & information stored = phenotype
, Genetics 214
▪ Watson & Crick were awarded the Nobel Prize in 1962 for the structure of DNA
▪ Nucleotides: sugar group, phosphate group and a base (A, T, G & C)
▪ Nitrogenous bases attach to sugars of DNA strands which attaches to a phosphate
group in a double helix ring shaped molecules
▪ Adenine (A) pairs with thymine (T) & guanine (G) pairs with cytosine (C) in DNA.
Adenine pairs with uracil (U) in RNA
▪ Sugar-phosphate backbone: DNA is a polymer made of nucleotide units
▪ DNA strands held together by hydrogen bonds between bases on adjacent strands
Replication errors cause mutations = new variations
▪ DNA: chemical name for the long, stringy chromosomes inside of cells
▪ Genes: segments of DNA coding for proteins
▪ Alleles: different version of the same gene with small differences in their nucleotide
sequences
Central dogma: how genes create phenotypes from DNA to proteins
▪ DNA sequence - transcription - mRNA sequence (amino acid coded in 3 codons
identical to coding strand with a U base not T base) - translation - protein
▪ Bases on a single strand act as a code
▪ 3 letter codons form coding for amino acids (building blocks of proteins)
▪ DNA stores information to run the cell
▪ RNA polymerase enzyme transcribes DNA into mRNA (messenger ribonucleic acid)
▪ mRNA splits apart the 2 strands that form the double helix & reads the template
strand copying the sequence of nucleotides from the coding strand
▪ Only difference between the mRNA and original DNA is that uracil (U) with a similar
structure replaces thymine (T). All the other bases remain the same
▪ mRNA carries genetic code out of the cell nucleus to the cytoplasm where protein
synthesis occurs
▪ Translation process turns the mRNAs code into proteins
▪ Ribosomes carry out the process building up proteins from the amino acids coded for
▪ Proteins perform the functions in the cells
Modern evolutionary synthesis
▪ Rediscovery of Mendel’s work
▪ Amalgamation of Mendelian & Darwinian principles
▪ Origin of population & quantitative genetics
Quantitative genomics: study of genetic basis of variation in quantitative traits
Combines traditional tools of genetics & molecular biology with modern statistics &
computer science to understand underlying genetic architecture of phenotypic variation
Used to study population structure of no. species (humans, plants and animals) = insight in
relationships between populations, genetic structure & investigate genetic basis of traits
(foraging behaviour, growth rate and disease resistance)
