Genetics With A Single Parent Flashcards
Intro
Many organisms reproduce asexually, as do nearly all body cells
All this involves genetics
Also asexual transfer of genetic information between generations even in sexual organisms
Parthenogenesis
A term for when a female can produce offspring either sexually or asexually eg bananas, potato, stick insects, some reptiles, haplodiploids.
Anisa gamy
The union of two gametes that differ in size. Males generally produce many smaller
gametes and females produce fewer larger gametes.
Patrilineal inheritance
The Y chromosome; differential (pseudo-autosomal) regions recombine with X where recombination takes place.
Many genes have been lost to the X or decayed due to mutation. The remaining genes tend to code for male traits e.g. SRY active early in development makes males male.
Many palindromes where Y can recombine with itself. Mapping Y chromosomes such as SRY reveals the evolution of males. There are parallels between the inheritance of Y chromosomes and the inheritance of surnames
Matrilineal inheritance
Mirabilis is a variegated plant: mixture of green and white patches on leaves.
Most branches – leaves blotchy green and white; some branches on same plant – all green or all
white.
Each branch has flowers, containing both pollen and egg (i.e., genetics of branches, as well as the whole plant, can be studied).
Check table on document
I.e in every case the phenotype of the progeny is that of the mother; the father’s phenotype has no effect
Gene in cytoplasm, passed down only through female parent; number of white or green chloroplasts passed on to each egg varying at random between variegated plants.
This is cytoplasmic inheritance, and the genes are on the chloroplast
Mitochondria genetics
Slow-growth mutants in Neurospora e.g. “poky”; phenotype can be transferred with microinjection of cytoplasm - i.e. mitochondrial.
Mapping cytoplasmic genes: Crosses between mating types in Chlamydomonas resistant to different drugs; three-point crosses - but gene order changes in each experiment. Resolution - the mitochondrial map is circular (electron microscope proves it).
The origin of mitochondria - the endosymbiotic theory. Mitochondrial inheritance in humans,
Leber’s hereditary optic neuropathy. Many diseases associated with deletions in the mitochondrial genome e.g. the muscle weakness called ragged red fibres.
Maternally inherited bacteria
E.g. Wolbachia Passed on through the female cytoplasm; males are evolutionary dead ends. Can stop male development, make males infertile, or kill adult males.
Potential biological control.
Did Adam meet Eve? Variance in male and female reproductive success and tracing the focal ancestor of men and women
