143

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 ...


80

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 someone said &...


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 ...


29

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 ...


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 ...


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 ...


21

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 ...


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 ...


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

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

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)


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 ...


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

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

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

Due to some very apt criticism regarding my comment on the question I am going to rephrase it as an answer. It is not so much that the question has an invalid premise, but that the cited article that generated the question is based on an invalid premise. We know as a fact that homosexuals do conceive children.1 The idea that they do not is false and the ...


10

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 ...


10

According to the US National Institutes of Health (NIH) (emphasis added): Researchers used to think that eye color was determined by a single gene and followed a simple inheritance pattern in which brown eyes were dominant to blue eyes. Under this model, it was believed that parents who both had blue eyes could not have a child with brown eyes. However, ...


10

Yes, this is accurate. The Wikipedia article has a good summary of the science, and you can also read this leaflet from the NHS in the UK. Your question about why this matters so much is a good one, and the answer is really interesting. It turns out that being "AS" (meaning one good gene and one faulty one) makes it very difficult for you to get malaria. So ...


8

I wish to add to the above answer. Approximately 9% of the genome is viral in origin, but current research suggests there is less of 'you' than there are other viral related sequences. Here is a very nice listing of the percentages of various genetic elements within the human genome: http://sandwalk.blogspot.com/2008/02/theme-genomes-junk-dna.html Although ...


8

This is not my area of scientific expertise. I cannot say if this study by Wilder et al is correct or not, but I can read the study and compare their conclusions to Baumeister's. Wilder et al conclude that women outnumber men in human ancestry, but they do not conclude that the ratio is two to one. They make a different conclusion about a two to one ratio, ...


8

While it is certainly not obvious to the eye, the fact that the closest relatives of crocodiles are birds appears to be well-established. These two clades are the only living members of a group known as archosaurs (Green et al. 2014): Crocodilians, birds, dinosaurs, and pterosaurs are a monophyletic group known as the archosaurs. Crocodilians and birds ...


6

I'll avoid trying to define what "additional genetic information" means and focus on what the Lenski experiment actually shows. The claim from Ken Ham that an existing gene was switched on is essentially correct, although there is a bit more to the whole thing. The genetic background for the evolution of the Cit+ trait is examined in Detail in the paper "...


6

The BBC produced a programme called "No More Boys and Girls", where they tried to do the opposite of most studies which attempt to measure the amount of gendered behaviour in infants or monkeys. The programme included the opinions of experts in the field, who suggested that while male and female brains are different from birth the differences are relatively ...


6

This is not an exhaustive or conclusive answer, but I've come across experiments that show the following: In a paper from 1980, Danielle Dhouailly, Margareth Hardy, and Philippe Sengel succeeded in introducing retinoic acid (Vitamin A) to induce feathers instead of scales to form on chicken feet Matthew Harris and John Falon were able to cause feathers on ...


6

There is evidence of the opposite. Here are some comprehensive references that based on genetic evidence show how actual human evolution probably happened. Some basics: Pääbo, 2003. Stringer, 2012 comments on what makes modern humans human - of course without mentioning members of the Suidae family. Finally, the introduction of Harris and Nielsen, 2016 ...


5

In general terms, inbreeding is dangerous because it increases the chances of homozygosity. This means that for a particular gene, identical alleles of the gene are present on both homologous chromosomes. Those individuals result of the inbreeding have more chances of having recessive or deleterious traits. These are generally 'invisible', they don't ...


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