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EDITING EPIGENETICS. "Assuming some epigenetic defects are nevertheless transmitted to the next generation, sexual reproduction and outbreeding would be advantageous because they provide the opportunity for their removal at the next meiosis. Inbreeding would be disadvantageous, because it increases the probability that epigenetic defects would become homozygous and could no longer be removed by recombination." https://lnkd.in/dx9WaSq View in LinkedIn

EPIGENETIC REPROGRAMMING. "It is proposed that the absence of a functionally important methyl group in a promotor or operater region produces a recombinator or signal for the initiation of recombination. The formation of hybrid DNA in this region then allows the lost methyl groups to be replaced by maintenance methylase activity. The removal of epigenetic defects by recombination during meiosis therefore becomes an essential part of a reprogramming and rejuvenation process." http://europepmc.org/abstract/med/6400219 View in LinkedIn

CONFINED. "There is also evidence that recombination at meiosis is largely confined to structural genes or adjacent DNA." https://lnkd.in/dx9WaSq View in LinkedIn

EPIGENETICS. "Evidence is now available which strongly indicates that the control of gene activity in higher organisms depends in part on the pattern of cytosine methylation in DNA, and that this pattern is inherited through the activity of a maintenance methylase. Epigenetic defects may arise by the loss of methyl groups which the methylase is unable to replace in somatic and also germ line cells, if de novo methylation cannot occur." https://lnkd.in/dx9WaSq View in LinkedIn

BIOLOGICAL FUNCTIONS OF MEIOSIS #4. "Fourth, that it helps maintain the immortality of the germ line, possible by a process of rejuvenation involving the removal of faulty RNA and protein molecules, or by the elimination of defective meiocytes." https://lnkd.in/dx9WaSq View in LinkedIn

WHY LINEAR #2. "Even crossing over between one linear and one circular chromosome will yield a linear dicentric that would also be unstable. The advent of sexual crosses may well have driven the advent of the linear chromosome: An ancestral protoeukaryote might have had two circular chromosomes with centromeres; their recombination would have yielded a circular dicentric that, when subjected to incomplete breakage-fusion-reunion cycles, could have given rise to linear chromosomes." https://lnkd.in/ebVhXPf View in LinkedIn

REPETITIVE ELEMENT PLAGUE. "The Group II introns residing in the genome of the ingested future mitochondrion are proposed to have colonized the host genome resulting in a large number of repetitive elements." https://lnkd.in/d8Qr_bk View in LinkedIn

WHY LINEAR #1. "The earliest protoeukaryotes may have had only one or a few linear chromosomes encompassing the entire genome (which also necessitated the evolution of centromeres and telomeres to allow faithful segregation and protect the ends from decay). Linear chromosomes are required because crossing over between two circular chromosomes generates a circular dicentric that is unstable (the chromosome is broken if the two centromeres attach to opposite spindle microtubules)." http://cshperspectives.cshlp.org/content/6/3/a016154.full View in LinkedIn

GROUP II INTRONS. "They can also spread through the genome by a similar, but less efficient reaction at ectopic sites. The phagocytosis of an α-proteobacterial cell by archaeal (or actinobacterial) eukaryotic precursor could have been accompanied by massive invasion of Group II introns." https://lnkd.in/d8Qr_bk View in LinkedIn

WHY LINEAR CHROMOSOMES? "There are several reasons to suggest that protoeukaryotes had linear chromosomes, or at least that these arose when meiosis evolved." https://lnkd.in/ebVhXPf View in LinkedIn