sections two - jane farrar - lecture 1

Within cells, structures called chromosomes contain genetic material in the form of DNA (deoxyribonucleic acid)

Each chromosome contains one long DNA molecule with hundreds or thousands of genes

Genes are the units of inheritance - they encode information for building the molecules synthesized within the cell

The genetic information encoded by DNA directs the development of an organism and the maintenance of cells in the organism

expression of genes -

transcription of genes- dna information used ot make rna

there is three billion bases in our genome

approx 1/1000 bases varies between different people

there are 7000 diseases in humans that are caused by a mendelian - due to a single gene mutation

twenty three pairs of chromosones in humans

Not all genes are active in all cell types. Genes make RNA which is translated into proteins, the building blocks required for each cell to function. Different cell types need different proteins to function.

Mutations in a single gene that give rise to a disease are called single gene defects (or Mendelian disorders after Gregor Mendel) - eg cystic fibrosis

the central dogma states that all genetic information is only passed one way DNA→ RNA→ Protein and this gentic information deos not move the other way

only about 1 % of our total genome codes for rna that codes for protein - laot of it codes for non coding rna

gene expression means transferring the gentic information from gene to cellular product

An organism’s genome is its entire “library” of genetic instructions u Genomics is the study of sets of genes in one or more species u Proteomics is the study of whole sets of proteins and their properties

the first complete human genome was published in 2003

it has dropped in price to have ur genome sequenceed since this

quantitative traits= (polygenic / complex disorders)

x linked disorders -

recessive

all daughters of an effected male will have the disease

50% of male children from a carrier female will have the disease & 50% of female children will be carriers

dominant

• Affected females have a 50% chance of passing the mutated X chromosome to each of their offspring (sons or daughters).

• Affected males will pass the mutated X chromosome to all their daughters but none of their sons since they pass the Y chromosome to their sons.

hamephilia - a potenital one time cure

1. Identification of disease genes & encoded proteins

2. Production of the recombinant FVIII & FIX proteins using recombinant DNA technology

3. Development of gene therapies using a non-harmful virus (AAV) to deliver the gene to the target cells (in the liver) - likely a ‘once off’ therapy

1. Production of safer vaccines: recombinant single subunit vaccines

e.g. hepatitis B vaccine; mRNA vaccines (COVID-19 RNA vaccines - Pfizer etc)

2. Production of recombinant human “therapeutic” proteins

e.g. insulin, growth hormone, clot dissolving proteins

3. Inherited disorders can be diagnosed prenatally

4. Prenatal genotyping - in vitro fertilisation & pre implantation diagnosis

5. Pharmacogenomics - using genomics to genotype populations & individuals

for genetic variants that influence responsiveness to drug therapies.

6. Forensics - role of genetic information in resolving crimes, person identification etc

CSI of sorts

pharmacogentics - this is understanding the individual reaction to some drugs

by studying and potentially finding the genes that cause this effect we could make drugs with a lower theraputic index available for use .

example

CYP2D6- this is the gene that codes for the enzyme that allows for codiene to be made into morphine -Codeine has a 200x lower affinity for mu opioid receptors in brain than morphine

some people entirely lack this gene and cannot process codeine - this is approx 10 % of caucasians

Recombinant DNA refers to DNA molecules that are artificially created by combining genetic material from different sources.