Assuming you’ve read previous links about mixed race fertility issues and health problems.
“Most evolutionary biologists distinguish one species from another based on reproductivity: members of different species either won’t* or can’t mate with one another, or, if they do, the resulting offspring are often sterile, unviable, or suffer some other sort of reduced fitness.
In a new paper published in the journal eLife, the researchers show that sex chromosomes evolve to be genetically incompatible between species faster than the rest of the genetic chromosomes and reveal the factors at play in this incompatibility.
*White women are a different species?
So sexual repulsion is part of species classification.
“This variation is manifested at the genetic level: sex generates some organisms within the species with lots of harmful mutations and some with relatively few. Supporters of the so-called mutational deterministic theory argue that if organisms with many mutations have disproportionately low survival chances, many bad mutations tend to die out with their hosts, generating a large number of organisms that are free from such mutations.”
“This sort of evolutionary game of cat and mouse is known as Red Queen evolution, from the character in Alice in Wonderland who insisted that one must run just to stay in the same place. Indeed, genes related to immunity are some of the fastest evolving we have. There is also recent evidence that species can increase the amount of genetic mixing they do when they sense that they are infected with a parasite. This means their offspring will be even more different from one another and their parents.”
Hard times make strong men.
“But neutral evolution can’t explain why some genes are evolving much faster than others. We measure the speed of gene evolution by comparing human DNA with that of other species, which also allows us to determine which genes are fast-evolving in humans alone. One fast-evolving gene is human accelerated region 1 (HAR1), which is needed during brain development. A random section of human DNA is on average more than 98% identical to the chimp comparator, but HAR1 is so fast evolving that it’s only around 85% similar.
Though scientists can see these changes are happening – and how quickly – we still don’t fully understand why fast evolution happens to some genes but not others. Originally thought to be the result of natural selection exclusively, we now know this isn’t always true.”
“The human mutation rate itself may also be changing. The main source of mutations in human DNA is the cell division process that creates sperm cells. The older males get, the more mutations occur in their sperm. So if their contribution to the gene pool changes – for example, if men delay having children – the mutation rate will change too. This sets the rate of neutral evolution.”
I have covered paternal age before. Few times.
Men delaying fatherhood is killing the West more than low birth rates. Having a few sprogs when you’re older only works if they’re higher quality than you could’ve had earlier.
Although obviously the birth rate CANNOT rise without marriage rates rising first.
“This study addresses the question ‘Are humans still evolving?’, and the answer is ‘Absolutely,'” study team member Benjamin Voight”
“The researchers also found positive selection in four pigment genes important for lighter skin in Europeans that were not known before. Scientists think humans evolved lighter skin in Europe as an adaptation to less sunlight.”
or it could be like domesticating foxes and be a visible side effect of lower criminal aggression, more civilization?
just test albinos in non-white groups
“And in East Asians, they found strong evidence of positive selection in genes involved in the production of alcohol dehydrogenase (ADH), a protein necessary for breaking down alcohol. Many East Asians can’t metabolize alcohol because they carry a mutation that prevents them from making ADH. The new finding suggests that the mutation may confer some currently unknown additional benefit.”
naturalistic fallacy, mutations can hold you back too
for example, if being able to produce it made you more prone to alcoholism, a disadvantage
“Only a few genetic changes are needed to spur the evolution of new species—even if the original populations are still in contact and exchanging genes.
Multiculturalism isn’t the risk you think it is.
[The risk to democracy, however….
Once started, however, evolutionary divergence evolves rapidly, ultimately leading to fully genetically isolated species, report scientists.”
“”Our work suggests that a few advantageous mutations are enough to cause a ‘tug-of-war’ between natural selection and gene flow, which can lead to rapidly diverging genomes,” Kronforst said.”
“A study of diverse African groups by geneticists has identified new genetic variants associated with skin pigmentation. The findings help explain the vast range of skin color on the African continent, shed light on human evolution and inform an understanding of the genetic risk factors for conditions such as skin cancer.”
The one tribe in Africa thing was always a myth.
“The findings suggest that about 9 percent of the human genes examined are undergoing rapid evolution.
“Our study suggests that natural selection has played an important role in patterning the human genome,” said Carlos Bustamante, a biologist at Cornell University.
A separate study announced last month indicated the human brain is still evolving, too.
Compared to chimps …”
If there’s reproduction, there’s evolution.
“Another 13 percent of the genes examined in the study showed evidence for negative selection, whereby harmful mutations are weeded out of the population. These included some genes implicated in hereditary diseases, such as muscular dystrophy and Usher syndrome. The latter is the most common cause of congenital blindness and deafness in developed countries.
Medical geneticists are interested in finding genes sensitive to negative selection because they might one day be useful for predicting an individual’s likelihood of developing a disease if the types of mutation to a gene and the environmental conditions are known.
Being able to determine which classes of genes are particularly vulnerable to negative selections is a first step, Bustamante said.”
“A newly-discovered species of ant supports a controversial theory of species formation. The ant, only found in a single patch of eucalyptus trees on the São Paulo State University campus in Brazil, branched off from its original species while living in the same colony, something thought rare in current models of evolutionary development.
“Most new species come about in geographic isolation,” said Christian Rabeling, assistant professor of biology at the University of Rochester. “We now have evidence that speciation can take place within a single colony.”
The findings by Rabeling and the research team were published today in the journal Current Biology.”
Where’s the evidence?