142

Normal viruses infect cells in order to take advantage of cellular mechanisms to reproduce themselves. A class of viruses known as "retroviruses" have a slightly peculiar mechanism to achieve this - they synthesise a special enzyme called "reverse transcriptase", which translates their own RNA into DNA which is incorporated into the host cell's genome. The ...


67

Finally, a question covering my nominal area of expertise. To answer this question meaningfully we'll need to define some concepts but first. Yes, sort of. The statement is factually correct for reasonable interpretations. So, on to the terms. I'll link to a more specific stackexchange to support the definitions Homology. To draw an analogy: If ...


34

The only genetic difference between men and women is that men have 1 Y chromosome and 1 X chromosome on their sex determinative chromosome. The Human Genome The human (Homo sapiens) genome is stored on 23 chromosome pairs and in the small mitochondrial DNA. Twenty-two of the 23 chromosomes belong to autosomal chromosome pairs, while the remaining ...


30

In this Nature Genetics paper, Gene-culture coevolution between cattle milk protein genes and human lactase genes Nature Genetics 35, 311 - 313 (2003), the variants in Cattle milk proteins and Human lactase persistence genes were analysed. (Lactase persistence means that adults can keep digesting lactose, while normally the lactase gene switches off after ...


28

Yes, genetically modified organisms (GMOs) are safe to consume. The American Association for the Advancement of Science, American Medical Association, World Health Organization, Food and Drug Administration, EU researchers all agree that GMOs are safe to eat. From the American Medical Association: Bioengineered foods have been consumed for close to 20 ...


28

According to an article in Marianne2 [French source], Loret's DNA was compared to that of Hitler's known male relatives, who must share a Y chromosome with Hitler. The results were that Loret cannot be Hitler's son. Those Y chromosomes can be considered partial, indirect samples of Hitler's DNA.


27

NO, not all pure white cats with blue eyes are deaf, however: From FabCats: In cats, congenital deafness is seen almost exclusively in white coated individuals. The deafness is caused by degeneration of the auditory apparatus of the inner ear and may affect one ear (unilateral) or both (bilateral). Breeding studies have defined the ...


25

I’m sorry, this is a long one. Unfortunately, the topic is complicated and I try to make it as understandable as possible. I’ll omit most of the technical details since they are hard to explain and don’t add a lot. Executive Summary (“tl;dr”) Epigenetic modifications do not constitute, nor enable, Lamarckian inheritance. Papers and reviews that claim this ...


25

We share a large amount of our DNA in common with all mammals through our shared evolutionary past. But I think you have confused two different ideas. Sharing 99% of genes is not the same as sharing 99% of DNA. While we may have nearly the same number and type of genes (i.e. rat genes have counterparts in the human genome) it does not mean that these genes ...


24

Yes, it is true to the extent that we can date accurately (see the Wikipedia links you provided, or this summary article). The best estimates right now are that Mitochondrial Eve lived 200+-13 kya, while Y-chromosomal Adam lived 142+-15 kya. It is also true that Genesis describes Noah and his three sons (one Y chromosome) and his wife and sons' wives (4 ...


24

Scientists from Cambridge University found that boys and girls are different (sexual dimorphism) even from day one. They exposed infants one day old to a thing and a face, and measured differences in interest (looking time). Neither the test person nor the timer knew which sex each infant was. The abstract from the 2000 study, "Sex differences in human ...


24

Reasons for switching? Generally today, in the western world, left-handed people are equally accepted as right-handed people and should not experience any major drawbacks. Today, a child can easily work with the left hand. Thanks to some tools such as scissors, writing pads and pens for left-handed no problems are expected. If a child does have bad deal, ...


23

This article has already been well-covered on the Internet. dinosaurs.about.com says "a complete hoax, albeit a very entertaining one." Snopes says "False" and explains the image is a kangaroo. Hoax-Slayer says "Hoax" and attributes the origin to "NewsHound, a website that publishes all manner of fanciful nonsense disguised as news reports." That's Nonsense ...


22

The first important point that is completely misrepresented in most articles I've seen about this is that Tifton 85 is not a genetically modified grass, but was created conventionally by crossing Tifton 292 and Tifton 68. See this article about the history and creaton of Tifton 85 bermudagrass for more information. Using this event to highlight the dangers ...


20

I would tend to think this is more a case of confirmation bias than anything else when trying to correlate red hair to temper (even your question cites a counter case with "Allie"). Numerous studies have been made between hair colour and various other traits, and they all pretty much come up with poor correlations in terms of actual personality. The ...


19

This answer has three sections: Is human intelligence declining? No. Is the genetic foundation of human intelligence eroding? This has not been shown. Are other factors influencing the genetic component of intelligence? Probably. Is intelligence declining? No, human intelligence is not declining. In fact, it is increasing. This is actually stated in the ...


17

Perhaps one of the most famous papers related to this is: Zachary D. Blount, Christina Z. Borland, and Richard E. Lenski, Historical contingency and the evolution of a key innovation in an experimental population of Escherichia coli. PNAS June 10, 2008 vol. 105 no. 23 7899-7906, doi: 10.1073/pnas.0803151105 As part of a two decade experiment, carefully ...


16

TL;DR: Maybe. Maybe Ahkenazi Jews score somewhere between 0.3 and 1 SD higher on IQ tests or verbal IQ. The genetic explanation in the question (disease-conferring genes are also intelligence-boosting genes, there was no bottleneck, but directional selection) has come under criticism. From your question it's unclear whether you want to know whether ethnic ...


16

No, twins do not have any special magical powers, despite a number of studies investigating the claim. A lightweight study was done in 1993 to examine if identical twins tended to have similarities in thinking, independent of any Extrasensory Perception (ESP). Susan Blackmore and Frances Chamberlain, ESP and Thought Concordance in Twins: A Method of ...


15

While I find the above answer accurate, I think it needs further clarification because it answers a question that is different from the one that was asked. The question was: "Is IQ (mainly) a genetically inherited trait?" The answer related not to how heritable IQ is, but to how heritable individual differences in IQ are. The point of confusion is that '...


15

It all depends on what you mean by "own". The major issue is that of patents of individual genes, particularly in the United States. A study in 2005 published in Science suggested 20% of human gene DNA sequences were patented and that some genes were patented as many as 20 times. But (in theory at least) each patent is not of the gene itself, but of its ...


14

Two things that are often overlooked in discussions of evolution, particularly when it comes to sexual behaviour, are sexually antagonistic traits and epigenetics. Recent studies indicate that homosexuality may be due to a normally beneficial epigenetic mechanism that occasionally malfunctions. If this is the case, then homosexuality is an abnormal ...


14

The claim that we share 50% of our DNA is likely a misquote of an older claim, that we share 50% of our genes with bananas. Both claims, as best I can tell, are false. I'll address each claim in turn. 50% of our DNA? The idea that we share 50% of our DNA is, by most obvious definitions of what that might mean, completely false, and trivially so. Per ...


13

No. Max Ingman and Ulf Gyllensten, Mitochondrial Genome Variation and Evolutionary History of Australian and New Guinean Aborigines, Genome Res. 2003. 13: 1600-1606, doi: 10.1101/gr.686603 This paper looked at the genetic diversity of Australian Aborigines and other indigenous populations in the area. It concludes: The proposed genetic separation among ...


12

No. There has been significant research into the genetics of Jewish populations over the past 20 years and "no evidence of a hypothetical Khazars' contribution to the Ashkenazi gene pool has ever been found." (Marina Faerman, Population Genetics of the Ashkenazim)


12

Your linked article has its own pointers to the issue: it says that the screening for being a carrier of a single mutation for beta thalassemia is compulsory and that the state (with religious backing) prevents marriage between carriers even if unrelated. This degree of compulsion is moving towards a eugenics policy and is similar to the past compulsory ...


11

No, this grossly summarised version of the paper overstates its conclusions. The quoted media reports suggest that the mother's genes account for all of the (variation) in intelligence of male children. They echo the statement you quoted from the final paragraph of the paper, but this final paragraph summary is an overstatement of the argument put forward ...


11

The hypothesis that humans descended from chimp-pig hybrids can be denied on the following points. Hybrids between different orders of mammals are very rare due to the genetic differences and differences in chromosome number. Despite McCarthy's suggestions to the contrary, reports of hybrids between different orders of mammal, though, are, literally, ...


10

A quick look around seems to show that although uncommon, it is not unique to have range animals poisoned by cyanide. It does not seem to be a "GM" issue(?). Many plants produce cyanide as a defence mechanism against browsers (mainly snail sized). If the plant is under stress (like when a drought occurs) the levels and concentration of this toxin increases ...


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