Recent comments in /f/askscience

CuppaJoe12 t1_j39j3n0 wrote

Reply to comment by everythingiscausal in Can parthenogenesis (virgin births) happen in mammals? by Fragrant_Novel_3907

With cloning you get an exact copy, at least in terms of DNA sequence. This is done by copying a body cell called a "diploid cell," which has a full copy of an individual's DNA.

With parthenogenesis, you do not get an exact copy. You take two haploid gametes, aka sex cells, and implant one into the other similar to how a sperm implants into an egg. The difference is that in this case, it is two egg cells ("oocytes") from a single mother instead of a sperm and an egg from two different parents.

Most genes (with a few exceptions, particularly for male offspring) consist of two copies, one from the father and one from the mother. The grandfather and grandmother of the parthenogenetic offspring.

Whereas the mother has one copy each from the grandmother and grandfather (again, with some exceptions) the parthenogenetic offspring might get two grandmother copies, or two grandfather copies, or it might be the same as the mother with one copy of each. However, with how many genes there are, there is essentially a zero% chance the offspring gets one of each for every gene like the mother has. Thus, its DNA is different from the mother.

This is the same reason you are not a genetic copy of your brothers and sisters. In this case, there are 4 grandparents and 4 possible parings instead of 2 grandparents and 3 pairings for parthenogenesis.

Edit: perhaps an easier way to explain this. If two clones or two identical twins were to mate, their offspring would be genetically identical to parthenogenetic offspring. It is the most extreme form of inbreeding possible, but each offspring would still have unique DNA like brothers and sisters are unique from each other.

8

Xilon-Diguus t1_j39cewg wrote

Reply to Is there abiotic way of mononucleotide polymerization? by kappusha

Yes, we polymerize nucleotides abiotically all the time wiki. Remember that it is energetically favorable, the enzyme is just positioning things in the right general location.

When things start to get to a certain length we start stitching things together, but that is more of a practical solution than any sort of biochemical limit.

The RNA world hypothesis accounts for this, you are really just researching if you think that it is likely to have happened that way at this point.

1

ExcelsiorStatistics t1_j399ykk wrote

Reply to Could aquifers be actively recharged? by smontanaro

An interesting accidental case study is the Thousand Springs area in south-central Idaho.

There were some naturally occurring springs there before farming and irrigation got going. The springs were substantially enhanced when a big network of surface canals were built in the late 19th century, and then substantially depleted as there was a transition to using well water and more efficient irrigation (edited to add: using sprinklers rather than flood irrigation). As butiwouldrathernot mentioned, the discharge and recharge happens on a timescale of decades.

When I lived in eastern Idaho a decade or so ago, there was a lively debate about whether we should deliberately run water through the canals all winter when the farmers were not using it, to recharge the aquifer and keep downstream wells from running dry.

4