Genetic Diversity Flashcards
What is a mutation?
Any change in the base sequence of chromosomes.
What is the difference between diploid and haploid cells?
Diploid cells contain two sets of each chromosome - one paternal, one maternal.
Haploid cells contain one set of each chromosome.
Name 4 different types of mutation
Substitution, Insertion, Deletion, and Chromosome mutations.
What are chromosome mutations?
Changes in the structure or number of whole chromosomes.
What is polyploidy?
A chromosome mutation which causes a change in whole sets of chromosomes when organisms contain 3 or more chromosome sets.
What is non-disjunction?
A chromosome mutation in which there is a change in the number of individual chromosomes. Sometimes individual homologous pairs fail to separate during meiosis. One example is Down’s syndrome
Does every base mutation cause a change in amino acid produced?
No due to the degenerate nature of the genetic code, in which most amino acids have more than one codon.
What is a frameshift mutation?
A frameshift mutation is a genetic mutation caused by a deletion or insertion in a base sequence that shifts the way the sequence is read. This is extremely likely to change amino acids and therefore polypeptides/ functional RNA produced.
Name some differences between mitosis and meiosis
Mitosis produces two genetically identical, diploid daughter cells.
Meiosis produces four haploid daughter cells. They will half the chromosomes of the parent cell.
What is crossing over in meiosis?
During meiosis I homologous chromosomes pair up and the chromatids wrap around each other at sections called chiasmata. Equivalent portions of the chromatids are then exchanged by tension causing them to break. This creates an almost infinite genetic diversity.
What is independent segregation?
During meiosis I, the homologous pairs of chromosomes arrange themselves randomly at the equator. One of each pair will pass to each daughter’s cell. This increases genetic diversity by two to the power of how many pairs of chromosomes there are.
How much does independent segregation increase diversity in humans?
Humans have 23 pairs of chromosomes so 2^23. Therefore there are 8388608 different combinations.
What is genetic diversity?
The total number of different alleles in a population.
What is a species?
Organisms that can interbreed to produce fertile, viable offspring.
What is directional selection?
Selection may favor individuals that vary in one direction to the mean.
