Genetics part 1 Flashcards
(64 cards)
Mendel’s First Law of Segregation:
Two copies of each particle one from each parent. They remain unaltered and one is passed on at random in each sperm/egg.
Mendel’s Second Law: Independent Assortment
Traits are inherited independently
Mendels Third Law Dominance
The inherited particles may be dominant or recessive.
What groups are in Archaea?
Includes groups like euryarchaeota and Crenarchaeota
How can point mutations in non-coding vs coding regions influence evolutionary comparisons between primate species?
Point mutations in non-coding regions often accumulate neutrally and can be used as molecular clocks while mutations in coding regions mat affect protein function and are subject to selection, providing insights into functional divergence.
Why are Pan troglodytes and Homo sapiens considered more closely related than either is to Gorilla gorilla?
Their DNA sequences have fewer nucleotide differences showing more recent common ancestor and greater genetic similarity especially in conserved genomic regions.
How can comparative genomics as shown in a DNA alignment table be used to reconstruct phylogenetic trees?
By counting number of sequence differences, scientists estimate evolutionary distance and construct cladograms and infer branching order in phylogenies.
How do loss of function mutations in pigmentation genes lead to albinism at the molecular level?
This mutations disrupt enzyme activity e.g tyrosinase or melanin transport preventing normal melanin biosynthesis in melanocytes leading to hypopigmentation.
Why is it unlikely that complex behavioural traits like anxiety can be explained by single mutations?
Such traits are polygenic and involve complex gene-environement interactions meaning many loci with small effects contribute to overall phenotype often modulated by life experiences
What evolutionary pressures might maintain variation in complex traits like anxiety within a population?
Balancing selection may preserve variation if different levels of traits e.g vigilance, reactivity, offer context dependent fitness advantages in different environments.
What molecular event intiates the transition from normal cells to precursor lesion in cancer evolution?
Accumulation of mutations due to imperfect DNA replication especially in genes regulating cell growth and repair.
What is a “driver mutation” in cancer, and how does it differ from a “passenger mutation”?
A driver mutation provides a growth advantage and promotes clonal expansion, while passenger mutations are neutral changes that do not contribute to cancer progression.
What is meant by “clonal sweep” in the context of cancer evolution?
The expansion of a single cell clone carrying a beneficial driver mutation that outcompetes others, leading to genetic homogeneity in that region of the tumor.
How does a primary tumor form from a precursor lesion
Throguh clonal expansion and driver mutations which cause cells to gain traits like uncontrolled growth resistance to apoptosis and invasion.
Why do cancer cells within the same tumor often show genetic diversity
ongoing mutations and selective pressures lead to intra-tumoral heterogeneity, resulting in subclones with different mutations and phenotypes.
What is the clinical significance of tumour heterogeneity in cancer treatment?
It complicates therapy because different clones may respond differently leading to drug resistance and treatment failure.
What are escape mutations
let virus escape the immune system by changing the spike protein just enough to reduce the effectiveness of neutralising antibodies.
problem: virus evolves in compelx unpredictable ways.
WHat is heredity in genetics
the passing on of traits from parents to offsring through genetic material DNA
Who is the father of genetics, why?
Gregor Mendel for disovering basic principles of inheritance using pea plants
How are genotype and phenotype linked
genotype determines which proteins are made, which then influence the phenotype; environment can also modify the outcome.
When do Mendels laws not apply perfectly?
When there are linked genes, codominance, incomplete dominance, polygenic traits/ epigenetic effects
Why is it important to know when and why genetics follows Mendel’s laws?
It helps predict inheritance patterns accurately and understand exceptions due to more complex genetic mechanisms.
Aristotle: spontaneous generation
3 kinds of plants and animals;
1) reproduce from seed/ from parents - one organism makes another similar organism
2) grows out of another organism - one organism gives rise to a different to a organism
3) arises spontaneously from non-living material (weeds, flies and maggots)
What is the scientific method in the birth of rationalism in 1500s-1600s
Make observations
Think of interesting questions? e.g why does this pattern occur?
Formulate hypotheses
develop testable predictions
gather data to test predictions
Refine, alter, expand or Reject Hypothesis.
develop general theories.
