Tag: genetics

A three-eared cat?

November 19, 2015 • 9:45 am

by Greg Mayer

The BBC reports on an abandoned cat with “three ears” found in Norfolk. Shelter staff at Feline Care Cat Rescue in East Harling have named him “Brian”*. [JAC: several readers also sent this to me.]

A three-eared cat from Norfolk (via BBC).
Brian, the three-eared cat from Norfolk (via the BBC).

I can’t recall ever seeing such a cat, and neither could the shelter’s vet, though Jerry had apprised us of the existence of extra-eared cats a while ago. The first thing that struck me is that the cat does not have three ears, but rather three ear pinnae. Ears, in a strict sense, are the paired sensory organs at the back of a vertebrate’s head that detect vibration and movement. The pinnae are the external elaborations for directing sound waves to the ears proper that are found in most mammals. (And also in Vulcans, who are not mammals, but who are renowned for their pointed pinnae, which led to some suggestions for a Star Trek-themed name for Brian.) Most vertebrates have ears, but relatively few have pinnae. Some, such as lizards, just have holes in the sides of their heads (you can look through a lizard’s head from one side to the other by looking into its ear opening), while others, such as frogs, have the tympanum (eardrum) exposed on the surface.

The second thing that occurred to me is that the extra ear pinna is moving in the opposite direction from a famous trait studied by the great geneticist Sewall Wright— otocephaly. Meaning literally “ear head”, in this condition the ear pinnae expand and extend under the ventral side of the head (1-5), the lower jaw fails to develop, and, in extreme cases, the entire front of the head fails to develop as though squeezed in from the sides, the eyes touching (7), merging (to form a cyclops: 8-9), and finally disappearing altogether in the highest grade otocephalic individuals (10-12).

Grades of otocephaly in guinea pigs (from Wright, 1935).
Grades of otocephaly in guinea pigs (from Wright, 1934).

I had read and studied Wright’s paper on otocephaly as a graduate student, as I was interested in the genetics of traits of large phenotypic effect in vertebrates, and Wright had studied otocephaly and polydactylism (extra toes) in guinea pigs. Polydactylism is much more interesting, as changes in digit number have been important in vertebrate evolution, and some rodents also show an approach to hoof development, which is very important in mammalian evolution, and usually involves changes in digit number. Otocephaly, in contrast, has not led to any evolutionary novelties, but rather is lethal in most cases– Wright referred to otocephalic individuals as “monsters”. The late Will Provine, in his masterful scientific biography of Wright, discusses the significance of his work on guinea pigs for the development of Wright’s ideas on the importance of multifactorial inheritance and non-genetic factors. (I should record here my mourning of Provine’s passing this past September, which Jerry first alerted us to. His Origin of Theoretical Population Genetics, recommended to me when I was an undergraduate by then Stony Brook geneticist Dick Koehn, was my first real introduction to the history of science as a serious discipline, and influenced me greatly. I was much pleased when he occasionally joined the discussion on my posts here at WEIT.)

Although not important evolutionarily, otocephaly, which is known to occur in many mammals, had cultural significance, which Wright well knew.  In his historical review of theories of the causation of otocephaly, he wrote the following passage, surely one of the most wonderfully erudite in all the literature of genetics:

We may pass rapidly over the theories of ancient times, according to which monsters were looked upon as the result of the play of the Gods, “ sports,” as signs of divine power or anger or as portents. The oldest known publication on the subject seems to be a brick  found in ASHURBANIPAL’S library in Nineveh which gives in cuneiform the prognostication appropriate to each of a remarkable list of monsters…

[I should add that Ashubanipal’s name is in all caps because it is the style of the journal Genetics to capitalize the names of cited authorities in its papers: he’s probably one of the few Assyrian emperors cited as a reference in the scientific literature!]

Having checked up on the genetics of the merger and disappearance of the ear pinnae, I got back to our cat with an extra pinna, and turned to my bookshelf for my copy of Genetics for Cat Breeders. There, on page 168, I found the entry for “Four-ears”. It is inherited as a recessive, denominated dp, with affected cats suffering reduced fitness (as determined by a deficiency of affected cats in crosses). The head shape is peculiar, the lower jaw a bit underdeveloped (like low grade otocephaly!), and the affected cats’ behavior is lethargic, suggesting some brain abnormality (again, as found in otocephaly). The authority is Little (1957). So, Brian the cat is doubly odd: he has one extra ear pinna, not the usual two extra (when there are extras). I can’t see his right side in the photo, but I’ll take the BBC’s word that he’s oddly asymmetrical in his ear pinna numbers.

Sarah Hartwell‘s Messybeast Cats website has compiled a number of cases of four eared cats (and other ear anomalies) reported in the media, along with useful explanatory diagrams, and also interesting discussion and illustrations of a number of facets of cat biology (for example, color patterns). In her section on facial deformities, some of the cats pictured look like they are otocephalic. (Although many such enthusiast websites are, at best, unreliable, I have found Messybeast to be quite reliable, for example in its explanation of “winged cats” [I once had a winged cat myself!].)

Little, C.C. 1957. Four-ears, a recessive mutation in the cat. Journal of Heredity 48:57. (not seen; shockingly, the University of Wisconsin, Madison– the ‘public ivy’ research giant, not my home campus– does not have an electronic subscription to this well known, historically important, Oxford University Press, journal)

Provine, W.B. 1971. Origin of Theoretical Population Genetics.University of Chicago Press, Chicago.

Provine, W.B. 1986. Sewall Wright and Evolutionary Biology. University of Chicago Press, Chicago.

Robinson, R. 1971. Genetics for Cat Breeders. Pergamon Press, Oxford.

Wright, S. 1934. On the genetics of subnormal development of the head (otocephaly) in the guinea pig. Genetics 19: 471–505. pdf

*Maybe the Romans did this to him.

US government opposes gene patenting

November 9, 2010 • 12:14 am

by Greg Mayer

In a move that got lost in the run up to the recent US elections, the Federal government has reversed its longstanding policy that genes are patentable. Released the Friday before the elections, and covered by the New York Times the following day, with a follow up article the day before the election, the Justice Department’s brief in the case argued that gene sequences unmodified by man are products of nature, and thus ineligible to be patented; and that isolating the sequence doesn’t change its status. Here’s a summary of the argument:

The district court [which invalidated two gene patents] correctly held, however, that genomic DNA that has merely been isolated from the human body, without further alteration or manipulation, is not patent-eligible. Unlike the genetically engineered microorganism in Chakrabarty [an earlier decision, allowing the patenting of genetically modified organisms], the unique chain of chemical base pairs that induces a human cell to express a BRCA protein is not a “human-made invention.” Nor is the fact that particular natural mutations in that unique chain increase a woman’s chance of contracting breast or ovarian cancer. Indeed, the relationship between a naturally occurring nucleotide sequence and the molecule it expresses in a human cell — that is, the relationship between genotype and phenotype — is simply a law of nature. The chemical structure of  native human genes is a product of nature, and it is no less a product of nature when that structure is “isolated” from its natural environment than are cotton fibers that have been separated from cotton seeds or coal that has been extracted from the earth.

The friend of the court brief was filed in an appeal of a case brought by a group of scientific and medical societies and individuals against Myriad Genetics, which had been granted patents on two genes associated with breast and ovarian cancer. In a surprise ruling last March, US District Court Judge Robert Sweet invalidated the patents (more on the ruling here and here), and the current brief was filed in response to Myriad’s appeal of the adverse ruling. The Feds argue that some aspects of Judge Sweet’s ruling erred, but that it’s main conclusion was correct: “…products of nature do not constitute patentable subject matter absent a change that results in a fundamentally new product. … [T]he purification of native DNA does not alter its essential characteristic– its nucleotide sequence– that is defined by nature…” (pp. 107 & 132 of the ruling, full text here).

The Federal position comes as good news to the scientists and medical groups involved, and to anyone who wants the law to make  sense. The notion that a gene is a human invention, rather than a product of nature, is absurd to any biologist (unless perhaps you were granted one of these bogus patents, which may be one of those cases where, as Upton Sinclair put it, it is difficult to get a man to understand something, when his salary depends upon his not understanding it). This is one instance in which the Obama administration has followed up on his promise that “Science and the scientific process must inform and guide decisions of my Administration on a wide range of issues”.

Russell Blackford has noticed the new anti-patent brief, and also had a nice overview of some of the issues at the time of Sweet’s ruling. NPR also noticed the new brief a few days later.