Fossils from 40 to 55 million years before the Cambrian found

Creationists are fond of considering the rapid appearance of many animal phyla in the fossil record of the Cambrian and claiming that there is  no fossil evidence of animals before the Cambrian.

Here Chen et al describe a tiny but complex bilaterian (ie possessing mirror symmetry like many modern animals) fossil animal dating from a t least 40 million years before the Cambrian

Chen et al, Science 305, 218 - 222 (July 2004). Go here for the abstract

Detailed Comparison of Chimp Chromosome 22 and Human Chromosome 21

28 May 2004

A group of scientists known as the International Chimpanzee Chromosome 22 Consortium have published their detailed sequence of chimp chromosome 22 and their nucleotide by nucleotide comparison with the equivalent chromosome 21.  They found a surprising degree of difference in protein coding regions. Highlights include the fact that 1.44% of nucleotides are different; protein coding regions have about as much difference as non-coding genomic regions; 179 out of 231 genes are identical in length and of these 140 have changes in one or more amino acid.

International Chimpanzee Chromosome 22 Consortium, Nature 429, 382 - 388 here

New hominin species just after human-chimp divergence

25 March 2004

Haile-Selassie et al have assessed recent dental fossil discoveries in the Awash region, and have concluded that Ardipthecus kadabba is a separate species not a subspecies of A ramidus which is found nearly a million years later.  A kadabba is the earliest known species after the human-chimpanzee split.

Haile-Selassie et al, Late Miocene Teeth from Middle Awash, Ethiopia, and Early Hominid Dental Evolution, Science 303, 1503 - 1505 (2004)

Oldest marsupial discovered

5 January 2004

Luo and colleagues have announced the discovery of the oldest fossil in the lineage leading to modern marsupials. Sinodelphys szalayi is a small tree climbing animal from the Yixian formation dated to 125 million years ago. This makes Sinodelphys the same age as the earliest known placental mammal, Eomaia scansoria, described last year.

Luo et al, An Early Cretaceous Tribosphenic Mammal and Metatherian Evolution, Science 302, 1934 - 1940.  The abstract is available here.

Draft Chimp Genome published

13 December 2003

The National Human Genome Research Institute (NHGRI), one of the National Institutes of Health (NIH), today announced the first draft version of the genome sequence of the chimpanzee and its alignment with the human genome. All of the data have been deposited into free public databases and are now available for use by scientists around the world.  Go here for more information.

In a separate paper, Clark et al, Science 302, 1876 - 1877, compare chimp and human sequences to find genes that have undergone rapid change since the divergence of the two lineages from their common ancestor. By anchoring the observations with the mouse genome, the authors are able to determine wether genes are undergoing rapid evolution in the human or the chimp lineage.  Genes that have undergone rapid evoliution in humans  include those implicated in hearing and smelling.  Go here for an abstract of the paper.

Huge support for Big Bang Cosmology

10 November 2003

Max Tegmark and colleagues have just published data for 200,000 galaxies in the Sloan Digital Sky Survey. In particular they have analysed the measured matter density power spectrum (the clustering of galaxies). Their analysis can be used to derive cosmological parameters (much like the CMB anisotropy spectrum).

The measured cosmological parameters (such as the age of the universe) show  a very close match between the entirely different ways of measuring them.  Even more impressive, by combining the two types of data, very tight constraints can be put on somne of the parameters.  This is extremely strong evidence in favour of our current cosmology models.

Go here for the papers::

The paper describing the spectrum and how  it is measured.

The paper deriving the cosmological parameters

Could the universe be finite in extent?

9 October 2003

A report in Nature suggests  that the lack of power in the largest scale aniotropies of the Cosmic Microwave Background, can be explained by a finite universe with a dodecahedral topology.  Go here for more information

The fossil of the largst known rodent analysed - 700kg of rodent

5 October 2003

In Science, Sánchez-Villagra et al report on the anatomy of the largest known extinct rodent - ten times heavier than the largest living rodent, the capybara.  Phoberomys pattersoni comes from the upper Miocene of Venezuela and weighs in at 700kg or 1400 times that of a guinea pig.  Go here for the abstract

The role of Hox genes in the evolution of the body plan of cepahalopods

27 August 2003

Lee et al report work to investigate the expression of Hox genes during the development of squid.  The squid form part of the Lophotrochozoa, a clade that displays more body plan diversity than any other clade of animals.  Their work sheds light on the nature of te molecular processes which drive morphological change during evolution

Go here for the abstract

Y-chromosome sequenced - male genes maintained by a special mechanism.

20 June 2003

Rozen et al and Skaletsky et al report the sequencing of the male specific region of the Y-chromosome (MSY). One important finding is that gene conversion (non-reciprocal recombination) between the arms of the eight major palindromes in the MSY, appears to have replaced the process of crossing over which occurs in the autosomes and the X-chromosome as a mechanism of gene maintenance.

Nature journal is allowing free access to both papers and other related material here

New African human fossils reported: immediate ancestors of modern humans

11 June 2003

White et al report in Nature the discovery of fossil human crania from Herto, Middle Awash, Ethiopia, dates at between 150,000 and 164,000 years ago. These crania probably represent the immediate ancestors of anatomically modern humans being intermediate between modern humans and more archaic African fossils.

Go here for the abstract

Go here for free access to Nature's News and Views

Go here for Nature Science Update

Measurements of Big Bang afterglow confirm cosmological model;  see below for

30 May 2003

First year data from the Wilkinson Microwave Anisotropy Probe confirm key elements of the cosmological model: a universe expanding at the critical rate, flat space, 13.7 billion years old, 4% matter, 23% dark matter, 73% dark energy. The observations from WMAP of the fluctuations in the Cosmic Microwave Background (the afterglow from the Big Bang more than 13 billion years ago) confirm these predictions.  Go here for the NASA news item and here for the formal technical first year reports.

31st May: Update published by Seife in Science 300, 730 - 731, here

How do complex features evolve? Modeling shows how

9 May 2003

A constant refrain of creationists is the claim that evolution cannot explain complex features. This argument was famously proposed by William Paley in the 18th century, and has recently been revived by the Intelligent Design movement in a more sophisticated form, particularly by Michael Behe in his book, 'Darwin's Black Box'. The argument has been refuted, but the argument is constantly used by creationists and IDers.

Now, in Nature, Lenski et al show that complex features can evolve.  They use digital organisms to show that complex features can evolve by co-opting simpler features and even mildly deleterious mutations.

Go here for the abstract

Detailed Review article on genetics and the evolution of Man

25 April 2003

As part of Nature's celebration of the 50th anniversary of the discovery of the structure of DNA, Nature has a detailed review  article by Sean Carroll on the genetic basis for the evolutionary changes in our genome that make mankind what we are.  Carroll identifies the specific morphological and behavioural attributes that distinguish Homo sapiens from other great apes and assess the known evolutionary changes in the genome that contribute to these.  Go here for the abstract

Gorilla and chimpanzee numbers plummet - humans nearest relatives in danger

11 April 2003

A study in Nature just published shows that the numbers of apes in West Africa, the last stronghold of gorillas and the common chimpanzee have halved in the last 20 years.  As the authors say: 'Gorillas and common chimpanzees should be elevated immediately to 'critically endangered' status. Without aggressive investments in law enforcement, protected area management and Ebola prevention, the next decade will see our closest relatives pushed to the brink of extinction.  Go here for the abstract

Squirrel DNA reveals distribution affected by tectonic and sea-level changes

21 March 2003

In Science, Mercer and Roth demonstrate that the DNA of squirrels correlates well with distribution and isolation based on well known movements of the continents and rises and falls in sea level, leading to isolation and integration of populations.  Go here for the abstract

Oldest human footprints found

13 March 2003

Nature has a description of the oldest human footprints ever found.  Formed in volcanic ash, these footprints are fully bipedal and date to 350,000 years ago Go here for the abstract

Big Bang cosmology questioned

17 March 2003

Lieu and Hillman find in Astrophysical Journal Letters, that the propagation of light does not depend on quantisation of time.  In simple terms,  this means that they observe time as smooth, not divided into discrete but tiny parcels.  If confirmed, this leads to a problem for the Big Bang cosmology which, up to now, has relied on quantum uncertainty to blur out the universe at the Big Bang and avoid  a singularity at the beginning.  Go here for the abstract

New finds in Olduvai call Homo rudolfensis into question

21 February 2003

In Science, Blumenschine et al find a human mandible in Olduvai west that is similar to Kenyan KNMER 1470. Go here for the abstract

All carnivores in Madagascar have a common ancestor

13 February 2003

In Nature, Yoder et al show  that all the carnivores on Madagascar arose from a common ancestor. Go here for  the abstract

Four-winged Dinosaurs from China

23 January 2003

Discovery of fossils of four-winged dinosaurs (dromaeosaurs) with evidence of wing structures on all four limbs