Gammarus chevreuxi

Gammarus chevreuxi
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Crustacea
Class:	Malacostraca
Order:	Amphipoda
Family:	Gammaridae
Genus:	Gammarus
Species:	G. chevreuxi
Binomial name
	Gammarus chevreuxi; Sexton, 1913

Gammarus chevreuxi is a species of crustacean in the family Gammaridae. It was first described by Elsie Wilkins Sexton in 1913. The organism is very similar to Gammarus locusta, but there are certain constant characters which set it apart, for example, the antennae, the fourth side-plates and the third uropods.[1] It is found in various places in England, such as the Severn Estuary, and in Portugal.[2]

Eyes and heredity

The eyes of G. chevreuxi are made up of black facets separated by white pigment. A mutation causes red facets. The recessive nature of the gene means that red-eyed populations breed true, being homozygous, while heterozygous black eyed populations may have either red-eyed or black-eyed offspring, in an illustration of Mendel's law of segregation.[3]

Correspondingly the white pigment separating the facets maybe missing by another mutation. This characteristic is inherited independently of the colour of the facets, illustrating Mendel's law of independent assortment.[4]

References

E. W. Sexton (1913). "Description of a new species of brackish-water Gammarus, G. chevreuxi, n. sp". Journal of the Marine Biological Association of the United Kingdom. 9 (4): 542–545. doi:10.1017/S0025315400071551. Archived from the original on July 17, 2011. Retrieved March 28, 2008.
M. D. Subida, M. R. Cunha & M. H. Moreira (2005). "Life history, reproduction and production of Gammarus chevreuxi (Amphipoda; Gammaridae) in the Ria de Aveiro, northwestern Portugal". Journal of the North American Benthological Society. 24 (1): 82–100. doi:10.1899/0887-3593(2005)024<0082:LHRAPO>2.0.CO;2.
E. B. Ford (1960). Mendelism and Evolution (seventh ed.). Methuen & Co (London), and John Wiley & Sons (New York). pp. 4–6.
E. B. Ford (1960). Mendelism and Evolution (seventh ed.). Methuen & Co (London), and John Wiley & Sons (New York). pp. 7–11.

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[1] E. W. Sexton (1913). "Description of a new species of brackish-water Gammarus, G. chevreuxi, n. sp". Journal of the Marine Biological Association of the United Kingdom. 9 (4): 542–545. doi:10.1017/S0025315400071551. Archived from the original on July 17, 2011. Retrieved March 28, 2008.

[2] M. D. Subida, M. R. Cunha & M. H. Moreira (2005). "Life history, reproduction and production of Gammarus chevreuxi (Amphipoda; Gammaridae) in the Ria de Aveiro, northwestern Portugal". Journal of the North American Benthological Society. 24 (1): 82–100. doi:10.1899/0887-3593(2005)024<0082:LHRAPO>2.0.CO;2.

[3] E. B. Ford (1960). Mendelism and Evolution (seventh ed.). Methuen & Co (London), and John Wiley & Sons (New York). pp. 4–6.

[4] E. B. Ford (1960). Mendelism and Evolution (seventh ed.). Methuen & Co (London), and John Wiley & Sons (New York). pp. 7–11.