GENETICS AND GENETIC
ENGINEERING
WHAT IS GENETICS
Genetics is a branch of biology that studies heredity and variation in
organisms
Tries to explain similarities and differences between parents and offspring
Who was the ‘Father of Genetics’?
Gregor Mendel (1822-1884) → an Austrian monk
● Investigating the transfer of characteristics from 1 generation to next
● ‘Something’ is passed on from parent to offspring and that sexual
reproduction combines these ‘somethings' from each parent to produce
offspring which are unique, yet the same
WHAT ARE THE SOMETHINGS?
● Genes - which are part of DNA molecules in chromosomes
Genes and Alleles
Genes :
● Each chromatid made up of one helical DNA molecule
● Each DNA molecule made up of series of genes
Gene = Section of DNA (series of nucleotides/bases) that controls hereditary
characteristics (trait) ---> basic unit of hereditary in living organisms
● Humans - 20 000- 25 000
● Nearly all somatic cells have exact copy of all genes in that organism
● 2 of each kind of chromosome (maternal & paternal), each cell contains 2
of each kind of gene (before replication) versions = alleles
, ● Gene pool = set of all genes/genetic info in a population of sexually
reproductive organisms
-large gene pool = high genetic diversity and increased chance of
survival
-small gene pool = low genetic diversity and increased possibility of
instinction
HOW ACTIVE ARE GENES?
● Only genes that are needed are activated in different cells,
creating specific proteins that give particular cell type its
character
● Some genes play a role in early development of embryo and are
inactive thereafter
● Some are active in many types of cells, making proteins needed for
basic functions → ‘housekeeping cells’. Others are inactive most
of the time
● High proportion of genes are non-coding genes ( do not code for
proteins and only occur in-between coding sections)
NOTE
● Master control genes that determine way which body develops from single
zygote = hox genes
● Control of genes = epigenetics. The Human Epigenome Project aims to
document what switches genes on/off
ALLELES
Responsible for controlling different versions of a trait/characteristic found
in the same locus (position) on homologous chromosomes
HOW ARE ALLELES REPRESENTED ?
Letters
● Capital = dominant
● Lower case = recessive
ENGINEERING
WHAT IS GENETICS
Genetics is a branch of biology that studies heredity and variation in
organisms
Tries to explain similarities and differences between parents and offspring
Who was the ‘Father of Genetics’?
Gregor Mendel (1822-1884) → an Austrian monk
● Investigating the transfer of characteristics from 1 generation to next
● ‘Something’ is passed on from parent to offspring and that sexual
reproduction combines these ‘somethings' from each parent to produce
offspring which are unique, yet the same
WHAT ARE THE SOMETHINGS?
● Genes - which are part of DNA molecules in chromosomes
Genes and Alleles
Genes :
● Each chromatid made up of one helical DNA molecule
● Each DNA molecule made up of series of genes
Gene = Section of DNA (series of nucleotides/bases) that controls hereditary
characteristics (trait) ---> basic unit of hereditary in living organisms
● Humans - 20 000- 25 000
● Nearly all somatic cells have exact copy of all genes in that organism
● 2 of each kind of chromosome (maternal & paternal), each cell contains 2
of each kind of gene (before replication) versions = alleles
, ● Gene pool = set of all genes/genetic info in a population of sexually
reproductive organisms
-large gene pool = high genetic diversity and increased chance of
survival
-small gene pool = low genetic diversity and increased possibility of
instinction
HOW ACTIVE ARE GENES?
● Only genes that are needed are activated in different cells,
creating specific proteins that give particular cell type its
character
● Some genes play a role in early development of embryo and are
inactive thereafter
● Some are active in many types of cells, making proteins needed for
basic functions → ‘housekeeping cells’. Others are inactive most
of the time
● High proportion of genes are non-coding genes ( do not code for
proteins and only occur in-between coding sections)
NOTE
● Master control genes that determine way which body develops from single
zygote = hox genes
● Control of genes = epigenetics. The Human Epigenome Project aims to
document what switches genes on/off
ALLELES
Responsible for controlling different versions of a trait/characteristic found
in the same locus (position) on homologous chromosomes
HOW ARE ALLELES REPRESENTED ?
Letters
● Capital = dominant
● Lower case = recessive
