Cornell researchers have sequenced and analyzed the genome of a single-celled alga that belongs to the closest lineage to terrestrial plants and provides many clues to how aquatic plants first colonized land.
Plants & Animals
May 22, 2020
0
499
What drives the evolution of new species of sharks and rays? Traditionally, scientists thought it required species to be separated by geographic or spatial barriers, however a new study of elasmobranchs (the group of sharks ...
Ecology
May 19, 2020
0
7
By analysing virus genomes from over 7,500 people infected with Covid-19, a UCL-led research team has characterised patterns of diversity of SARS-CoV-2 virus genome, offering clues to direct drugs and vaccine targets.
Evolution
May 05, 2020
0
1216
Until recently, little was known about how transposable elements contribute to gene regulation. These are little pieces of DNA that can replicate themselves and spread out in the genome. Although they make up nearly half ...
Biotechnology
Apr 15, 2020
0
242
A new study led by the University of Kent has found evidence that human ancestors as recent as two million years ago may have regularly climbed trees.
Archaeology & Fossils
Mar 30, 2020
0
351
Early cave paintings of hunting scenes may give the impression our Stone Age ancestors lived mainly on chunks of meat, but plants—and the ability to unlock the glucose inside—were just as key to their survival.
Archaeology & Fossils
Mar 27, 2020
10
1333
New research shows that crustaceans such as shrimps, lobsters and crabs have more in common with their insect relatives than previously thought—when it comes to the structure of their brains.
Evolution
Mar 04, 2020
1
504
For three years, anthropologist Alan Rogers has attempted to solve an evolutionary puzzle. His research untangles millions of years of human evolution by analyzing DNA strands from ancient human species known as hominins. ...
Archaeology & Fossils
Feb 20, 2020
6
7555
The discovery of a new species of prehistoric reptile from Germany is reported this week in Scientific Reports. The anatomical features of the species, named Vellbergia bartholomaei, add to our understanding of the early ...
Archaeology & Fossils
Feb 20, 2020
0
115
The microbiome of our ancestors might have been more important for human evolution than previously thought, according to a new study published in Frontiers in Ecology and Evolution. An adaptive gut microbiome could have been ...
Evolution
Feb 19, 2020
1
507
An ancestor is a parent or (recursively) the parent of an ancestor (i.e., a grandparent, great-grandparent, great-great-grandparent, and so forth).
Two individuals have a genetic relationship if one is the ancestor of the other, or if they share a common ancestor. In evolutionary theory, species which share an evolutionary ancestor are said to be of common descent. However, this concept of ancestry does not apply to some bacteria and other organisms capable of horizontal gene transfer.
Assuming that all of an individual's ancestors are otherwise unrelated to each other, that individual has 2n ancestors in the nth generation before him and a total of about 2g+1 ancestors in the g generations before him. In practice, however, it is clear that the vast majority of ancestors of humans (and indeed any other species) are multiply related (see Pedigree collapse). Consider n = 40: the human species is surely more than 40 generations old, yet the number 240, approximately 1012 or one trillion, dwarfs the number of humans that have ever lived.
Ignoring the possibility of other inter-relationships (even distant ones) among ancestors, an individual has a total of 2046 ancestors up to the 10th generation, 1024 of which are 10th generation ancestors. With the same assumption, any given person has over a billion 30th generation ancestors (who lived roughly 1000 years ago) and this theoretical number increases past the estimated total population of the world in around AD 1000. (All of these ancestors will have contributed to one's autosomal DNA is concerned: this excludes Y-chromosomal DNA and mitochondrial DNA.)
Some cultures confer reverence to ancestors, both living and dead; in contrast, some more youth-oriented cultural contexts display less veneration of elders. In other cultural contexts, some people seek providence from their deceased ancestors; this practice is sometimes known as ancestor worship or, more accurately, ancestor veneration.
This text uses material from Wikipedia, licensed under CC BY-SA
