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Jul
28
revised Why isn't a virus “alive”?
rmv tangental parenthetical comment, and many minor fixes.
Jul
28
suggested suggested edit on Why isn't a virus “alive”?
Jul
28
comment Why isn't a virus “alive”?
One correction: by the suggested definition, mitochondria are alive since they have ribosomes. (See, e.g., Properties of human mitochondrial ribosomes).
Jul
4
answered Mitochondrial DNA and recombination
Jun
19
answered Why do neurons have a negative resting potential?
Jun
17
comment Are human males and females more genetically different than members of other species?
Males and females have essentially identical genomes (differing only in the very small Y and mitochondrial chromosomes), so they essentially don't differ at all. This is true in other mammals too.
Jun
14
answered Is there any source for raw data of SNP genotype frequency?
May
31
comment Identify this waterfowl species?
I don't think there's seasonal plumage change going on here. The white patches seem to be driven snow. The bird on the left is plastered like the tree on the right.
May
21
answered How did the activities of protocells become inheritable?
May
11
answered Which X-Y chromosomes have the developmental genes for mammals?
Feb
19
answered How can the child and the mother have different blood types?
Feb
8
answered A question regarding evolution
Jan
12
answered What type of cell do you start with in Meiosis?
Jan
12
comment What type of cell do you start with in Meiosis?
Unfortunately, this answer does not answer the main question, stated in the title as "What type of cell do you start with in Meiosis?" and in the last sentence of the question body as "what exactly is the starting cell called?".
Dec
26
comment What kind of event would cause the current Mitochondrial Eve to be replaced by a new one?
...while only half of the daughter's daughters will be carriers (plus half of the daughter's sons). This means that the most likely first appearance of the fertility advantage is between cousins: a daughter's son and the daughter of either sex child of the original women (excluding unlikely brother-sister matings). Two-thirds of these latter granddaughters are (probalistically) via sons; the other third via daughters. Thus, 2/3rds will not carry the original mDNA, and thus the original woman is not so likely to become a M-Eve.
Dec
26
comment What kind of event would cause the current Mitochondrial Eve to be replaced by a new one?
That would increase the probability that she could become a M-Eve, but does not assure it. First off, being recessive, none of the woman's children would have any advantage carrying the mutation, since they will mate with non-carriers and so not show the advantage. (Assume for discussion both her X's have the mutation.) Now note that of her grandchildren, one half of them will be carriers and one half of them not. Note also that all of the sons' daughters will be carriers (the X coming from her), while [continued in next comment]
Dec
25
comment What kind of event would cause the current Mitochondrial Eve to be replaced by a new one?
@terdon, yes, "the females of each generation that carry the mutation will consistently have more offspring, eventually the vast majority of the species will carry the mutation" is true, but it is not true that these females need have her mDNA. Her sons mated with non-sisters, so all their offspring, sons and daughters, will not have her mDNA, yet will have the advantageous mutation to the same extent.
Dec
23
awarded  Yearling
Dec
20
comment What kind of event would cause the current Mitochondrial Eve to be replaced by a new one?
@terdon, since you say "Of course the mutation would be in the nuclear genome", the scenario would not be likely to make the particular woman a Mitochondrial-Eve. Suppose she has 5 sons and 5 daughters, then the offspring of the 5 sons are just as likely to carry the advantageous nuclear mutation, and thereby be likely to have surviving descendants, yet the sons' children do not carry her mDNA. The population will not especially favor female-only descendants of the original woman, hence not favor her mitochondria, and not favor her becoming a M-Eve.
Dec
14
comment What kind of event would cause the current Mitochondrial Eve to be replaced by a new one?
Not correct, as such a mutation would pretty much have to be in the nuclear genome, not the mitochondrial genome. Being on a nuclear chromosome, it would spread to offspring of women who are not her mitochondrial descendants, and thus she would not become a mitochondrial eve.