Created @March 13, 2023 3:49 PM
Reviewed
Introduction to module
Understand some of the reasons why genetics is important to research and
medicine.
design drugs, understand disease, personalise treatment
Understand that model organisms are often used by geneticists to discover
and characterise genes and gene function.
criteria = known genome, short cycle, easy, can transfer knowledge to
humans, can modify
eg. caenorhabditis (nematode), arabidopsis (plant), mus (mice), danio
(zebra fish), saccharomyces (yeast)
drosophilia melanogaster = fruit fly - diploid, 7 day time egg (2000/female)
to adult, cheap/small, 4 chromosomes 15000 genes 140mill bp sequenced
in 2000, 75% human disease genes present and 50% proteins have
mammal equivalents, used for neurological diseases/aging/cancer etc
Mendelian Genetics I and II
Describe the main events of mitosis (pro-, prometa-, meta-, ana- and
telophase) and of cytokinesis in animal cells.
inter = uncoiled chromatin
pro = chromosome condense, centrioles divide and move apart
prometa = double chromosomes visible, spindles form, centrioles at poles
meta = chromosomes align, centromeres on metaphase plate
ana = centromeres split, daughter chromosomes to poles
telo = daughters at pole (cell plate in plants)
genetics 1
, cyto = cell splits
Outline the stages of meiosis: DNA replication, pairing of homologous
chromosomes to form bivalents, crossing over (recombination), first and second
meiotic division.
recombination in pro 1 = exchange of non sister chromatids at chiasma
1 splits chromosome homologs, 2 split sister chromatids
Compare mitosis and meiosis and explain the genetic significance of meiosis
in creation of haploid gametes and generation of genetic diversity.
meiosis = 1 diploid > 4 haploid gametes (diversity from recombination)
genetics 2
, mitosis = 1 diploid/haploid > 2 diploid/haploid (for growth/bacterial
reproduction)
Define the terms haploid, diploid, genotype, phenotype, gene, allele,
homozygote, and heterozygote.
haploid = 1 copy of each gene/set of chromosomes 1n eg. bacteria
diploid = 2 copies (matching homologous pairs)/sets of
chromosomes/genes 2n eg. humans
genotype = both copies of all sets of alleles in organism
genetics 3
, phenotype = observable property of organism (geno + environment eg.
OB gene obese mice, Antp antennae to legs in dros, ADE2 red yeast)
gene = DNA sequence coding for protein, unit of hereditary, on specific
region of chromosome
allele = different forms/DNA sequence of same gene (species all has same
set but diversity from different forms), may (INSa/INSb) or may not
(INSa/INSc)change protein sequence
homozygote = same alleles, hetero = different
Understand how the terms paternal generation (P) and their offspring (F1) and
their subsequent offspring (F2) relate to each other. Understand that test
crosses between two individuals can be used to study patterns of inheritance.
F = fillial generation
P > F1 > F2
Understand how alleles are defined as dominant or recessive and the term
wild type.
wild type = most commonly found in nature
eg. INSa/INSa (non diabetic - wild), INSb/INSb (neonatal diabetes -
mutant)
recessive = only phenotypically expressed when homosygote eg. INSb (no
insulin activity)
dominant = expressed when either homo or heterzygote eg. INSa
R/D only relevant when comparing two phenotypes eg. INSd is dominant
to INSa as D is disruptive/blocks normal A causing neonatal diabetes
Understand a monohybrid cross can be used to study different alleles of the
same gene.
homozygous/true breed P cross will result in all F1 heterozygous (shows
which allele is dom) > F2 3:1 dom:rec
Understand how a dihybrid cross can be used to study the alleles of two
genes that are on different chromosomes (independent segregation).
genetics 4