Lecture 52. Chromosomal (Segmental) Variation Flashcards
What are chromosomal mutations?
Change in the chromosome number per cell
Large-scale (segmental) change in chromosome structure
Visible by microscopy
Why investigate chromosomal mutations?
Cytological insight into meiosis
Medical insight in causes of genetic disease
Molecular insight of how genes interact throughout a genome
Evolutionary insight (e.g., origin of new species)
What does n mean in terms of chromosomes?
Number of chromosome sets
What does 1n represent?
Monoploid
What does 2n represent?
Diploid
What does 3n represent?
Triploid
What does 4n represent?
Tetraploid
What does aneuploid mean?
Change in number of some but not all chromosomes
Is monoploidy useful in most animal species?
No, it is non-viable in most animal species
In what animals is monoploidy useful?
Social insects (ants, bees and wasps)
Males are monoploid & develop by parthenogenesis (gametes from mitosis)
Why is monoploidy useful in plant breeding?
Pollen grains subjected to cold shock begin to divide
What is an example of a triploid plant?
Banana
What are examples of tetraploid plants?
Coffee, cotton, peanut, potato, oilseed rape
What are examples of hexaploid plants?
Oat and wheat
What is an example of an octaploid plant?
Strawberry