BIOL1003 Study Guide - Final Guide: Sickle-Cell Disease, Anemia, Chromatin
Genetics
The Study of Inheritance
• Heritability of traits is one of the major premises of natural selection.
• Very little known about nature of inheritance until 20th century: eg: conception by spirit
entering woman or averaging of parental traits in offspring.
Uses of Genetics
• Disease diagnosis and cure – eg: haemophilia, CF (first gene therapy developed 2016), sickle
cell anaemia and Rh blood type incompatibility.
• Crop and stock improvement
o Since over 11,000 years ago, eg: sheep: selection for milk, wheat (6000 years ago
developed tetraploids) and wool or figs: mass cloning for select size.
o Now: Genetic markers, fingerprinting and GMOs.
• Forensics – identity/paternity testing.
• Conservation – importance of maintaining genetic diversity → try to preserve extinct
species, eg: cheetahs lost most of their genetic diversity in the last ice age.
• Systematics:
o Early systematics based on physical similarities.
o Modern systematics based on evolutionary history – use morphological traits
(structure) but genetic features, eg: DNA, are more reliable for comparing species.
• Making sense of the Evolution module
Chromosomal Basis of Inheritance
The Gene
• Mendel hypothesised a factor that conveys traits from parent to
offspring (1860s).
• Iitiall kow as page 88 – the smallest particles representing
one hereditary characteristic.
• Gene first used in 1909 – the fundamental physical and functional unit of
heredity.
• 1910 – Morgas work with eye-colour gene is Drosophilia led to the
chromosome theory of inheritance, which states that genes are located
on chromosomes and that the behaviour of chromosomes during meiosis
aouts for Medels laws.
The
Chromosome
• Observed under the first microscopes that all organisms were made of
cells.
• Iitiall alled oloured odies.
• Chromosomes – a condensed form of proteins and nucleic acids carrying
genetic information.
• Chromosomes are only present and visible
during cell division.
• When the cell is not dividing, chromosomes
are relaxed and spread out in the nucleus and
called chromatin.
• Most multicellular organisms we know have an
even number of chromosomes.
• The chromosomes can be sorted into pairs of
similar shapes and sizes.
find more resources at oneclass.com
find more resources at oneclass.com
