Mitochondria inheritance and 3 parent babies Flashcards
what is heteroplasmy
two or more mtDNA types
what is the maternal bottleneck
where only a small number of mtDNA molecules in the mother are passed on to the next generation
The spindle of chromosomes is removed from the donor egg and discarded.
The spindle of chromosomes is removed from the intending mother’s egg and transferred to the ‘enucleated’ donor egg; the intending mother’s egg is discarded.
The reconstructed oocyte contains the intending mother’s nuclear DNA and donor’s mitochondrial DNA.
The egg is then fertilized with the intending father’s sperm.
The embryo develops in vitro and is transferred to the womb of the woman who will carry the child.
maternal spindle transfer MST
ethical considerations of maternal spindle transfer
higher risk of abnormalities
operator depended
manipulation and destruction of oocytes
The intending mother’s egg is fertilized by the intending father’s sperm.
The donor egg is also fertilized by the intending father’s sperm.
The pronuclei are removed from the single-celled zygote of the donor egg and discarded.
The pronuclei are removed from the intending mother’s fertilized egg and transferred to the enucleated fertilized donor egg. The enucleated fertilized egg of the intending mother is discarded.
The reconstructed embryo contains pronuclear DNA from the intending parents and healthy mitochondria from the donor.
The embryo develops in vitro and is transferred to the womb of the woman who will carry the child.
pro-nuclear transfer PNT
ethical considerations of PNT
operator dependet
manipulation and destruction of fertilised eggs
The primordial germ cell (oogonium) undergoes mitosis in the fetus; at birth, the primary oocyte arrests in prophase of meiosis I (prophase I).
Beginning at puberty, once per month, a primary oocyte completes meiosis I and begins meiosis II, before arresting at metaphase II. At this time the first polar body is produced. The resultant secondary oocyte and polar body are haploid.
The secondary oocyte is ovulated. If fertilized by a sperm, the secondary oocyte completes meiosis II and the second polar body (haploid) is formed.
The first polar body is haploid because it contains one of each chromosome; however, each chromosome has been replicated and thus consists of two chromatids. After fertilization, a set of chromatids will be extruded as a haploid polar body
polar body transfer 1
The chromosome spindle is removed from the donor egg and discarded.
The 1st polar body is removed from the intending mother’s egg and transferred to the enucleated donor egg; the intending mother’s egg is discarded.
The reconstructed oocyte contains the intending mother’s nuclear DNA and donor’s mitochondrial DNA.
The reconstructed egg is fertilized with the intending father’s sperm.
The embryo develops in vitro (PB2 extruded) and is transferred to the womb of the woman who will carry the child
polar body 2 transfer
The intending mother’s egg is fertilized by the intending father’s sperm. (not shown)
The donor egg is fertilized by the intending father’s sperm. (not shown)
The maternal pronuclei from the donor zygote is removed and discarded, leaving a half-enucleated egg.
The 2nd polar body from the intending mother’s zygote is transferred to the half-enucleated donor egg, which contains the paternal pronuclei and donor mtDNA.
The embryo develops in vitro and is transferred to the womb of the woman who will carry the child.
what does mtdna lack
introns
point mutation -MELAS ( mitochondrial encephlomyopathy with lactic acid and stroke) present with
short stature deaf epilepsy DM PIGEMNTARY retinopathy recurrent strokes
diabetes and deafness occur in all NIDDM muttuaion in 12s RRNA GENE preening with
hearing loss induced after contact with ahminoglycosides
what Is Leber hereditary optic neuropathy (LHON)
ophthalmological disorder, presenting mainly in young adult males
characterized by acute or subacute bilateral optic atrophy resulting in loss of central vision
incomplete penetrance
