Download Genetics

Genetics
2.1 What is Genetics
2.2 Inheritance
2.3 DNA
2.4 Mutations and Disease
2.5 Genetic Technologies
2.1 What is Genetics
• Genetics is the science of inheritance
• Genetic information is carried on
chromosomes in the nucleus of every
cell
• Chromosomes contain sequences of
DNA called genes
• Genes are the instructions for making
proteins
2.1 What is Genetics
• A chart depicting the chromosomes
possessed by an individual is called a
karyotype
• Gender is determined by the 23rd pair
of chromosomes called the sex
chromosomes (XX or XY)
• Karyotypes are commonly made after
amniocentesis
2.1 What is Genetics
• Chromosomes must be replicated and
distributed during cell division
• Mitosis: the division of autosomal
cells into two identical diploid
daughter cells
• Meiosis: the division of sex cells to
make four haploid gametes
2.1 What is Genetics
• Fertilization is the combining of two
haploid gametes to make a diploid
zygote
• By selectively breeding livestock and
crops humans have altered naturally
occurring species to suit our needs
2.2 Inheritance
• Gregor Mendel worked with pea
plants to discover the basic rules of
heredity
• Every trait is controlled by two
alternate forms of a gene called
alleles
• One allele may be dominant while the
other is recessive
2.2 Inheritance
• A Punnett square can be used to
determine the probable outcomes
from a single trait cross
• Important definitions: genotype,
phenotype, heterozygous,
homozygous
• Human blood types illustrate other
mechanisms of inheritance
2.2 Inheritance
• Sex-linked inheritance involves alleles
carried on the X chromosome (colour
blindness and hemophilia
2.3 DNA
• DNA: deoxyribonucleic acid
• DNA is a double helix consisting of
paired nucleotides
• The order of nucleotides determines
the sequence of amino acids in a
protein
• DNA is self replicating using a semiconservative process
2.4 Mutations and Disease
• A mutation is a change is the
sequences of bases in a DNA
molecule
• Mutations can be substitutions,
additions or deletions
• Addition and deletion mutations are
called frameshift mutations
2.4 Mutations and Disease
• Some mutations result in genetic
disease
• If the mutation is recessive then it is
possible for a person to be a carrier of
the disease
• The frequency of mutations are
increased by mutagens
• Some mutagens are carcinogens
2.4 Mutations and Disease
• A pedigree chart can be used to
determine the type of inheritance of a
genetic disease, to determine the
genotypes of individuals and to
identify carriers
• Royal family pedigree chart
2.5 Genetic Technology
• Genetic technologies include:
• Transgenics: using recombinant DNA
technology to modify the proteins
produced by an organism (AKA
genetic engineering or genetically
modified organisms)
• Gene therapy: replacing a defective
gene to cure a disease
2.5 Genetic Technology
• DNA fingerprinting: cutting DNA into
fragments and creating a unique
profile for an individual