non - mendelian genetics - lecture 12 Flashcards
where do we inherit our cytoplasmic organelles from? ( and thus the cytoplasmic DNA)
Our mothers
What is the size and nature of human mitochondrial genome?
26kb , not many introns , very compact , most of it is coding DNA
nuclear encoded mitochondrial proteins
Lots of mitochondria genes got incorporated into the nuclear genome
Definition of homoplasmy
all organelles are genitcally identical
Definition of heteroplasmy
multiple distinct DNA sequences within the cytoplasm of the cell
How does variegation come about in plant leaved?
Heterplasmy, which leads to different cells in the same organism being genetically different
What is genetic maternal effect?
The phenotype of the offspring is determined by the genotype of the mother . e.g , despite a paternal dominance, mother phenotype still expressed . Seen in snails
Inferring population history using mtDNA
individuals with recent common ancestors will have the same sequence with slight changes due to mutations
What is gene conversion?
the process whereby, during meiosis two chromosomes begin to cross over , but resolve the process differently
DSBR
Double strand break repair
SDSA
synthesis dependent strand annealing
What are homing endonuclease?
Stretches of DNA that code for sequences that both copy itself and cut the unoccupied allele at the correct insertion site
Why are homing endonuclease an issue?
They can increase their allele frequency greater than mendelian rates
What percentage of humans have B chromosomes?
5%
What Is a unique feature of human B -chromosomes ?
Cannot be transmitted through the generations
