Genetic Diversity Flashcards
Why is genetic diversity important?
Genetic Diversity is important because the environment and disease affect each individual differently. We need genetic diversity so that we don’t all get wiped out and become extinct (this is why biodiversity is important too!)
How is genetic diversity achieved?
Genetic diversity is achieved by the crossing over and randomization of genetic information that occurs during MEIOSIS.
What is fertilization?
Where the male gamete (1n) combines with the female gamete (1n) to restore the normal, doubled somatic cell chromosome number (i.e. diploid number, 2n), which then develops into an offspring with the genetic contributions from both parents.
When does genetic recombination occur, how does it occur and what does it cause?
It occurs at beginning of meiosis where pairs of homologous chromosomes exchange gene segments in a process called crossing over.This causes variation in chromosomes resulting in daughter cells being all genetically different.
What are some factors that contribute to genetic diversity?
1) Genetic recombination
2) Independent Assortment
3) Genetic mutation
4) Population mixing
Is it possible to be identical to someone else?
YES! If you are an identical twin (a zygote that replicates itself)
BUT….. EPIGENETIC tags will “turn some genes on” and “some genes off” resulting in the expression of genes in twins being different over time.
What can cause a mutation? (And no you don’t need to memorize everything at the back of this card if you get it wrong)
Mutagens such as UV rays, X rays, cigarette smoke, nuclear radiation, pesticides, herbicides, pollutants, chemicals.
When does a genetic mutation occur, how does it occur and what does it cause?
It is a change in gene structure that occurs at random with or without consequence (can be good OR bad).Mutations can cause mutated cells that may be destroyed or not and passed down to daughter cells by mitosis.
When does independent assortment occur, how does it occur and what does it cause?
It occurs during metaphase I of Meiosis where homologous chromosomes pair up, maternal and paternal chromosomes pair up differently each time. It’s important to note that chromosomes from mom and dad have the SAME GENES but DIFFERENT COPIES of those genes. This means the new egg and sperm cells randomly get different copies of genes.
What’s synapsis?
It’s the pairing of two homologous chromosomes during Prophase I of Meiosis.
When a diploid cell divides by Meiosis to produce gametes, each of its four daughter cells is genetically unique. This is due to two phenomena in Meiosis I. What are they? Explain.
Firstly is independent assortment which occurs in Metaphase I.
Because of independent assortment, each daughter cell randomly receives either a maternal homolog or paternal homolog from each chromosome pair.
Secondly crossing over which occurs in Prophase I. Crossing over is basically the exchange of genetic material between homologous chromosomes, during synapsis.
How does population mixing lead to genetic diversity?
Population mixing is the reproduction among individuals with different genetic characteristics which leads to genetic diversity.
