Evolution of Fish in Extreme Environments: Insights from the Magadi tilapia (Alcolapia grahami)
نویسندگان
چکیده
................................................................................................................................... 10 Introduction .............................................................................................................................. 11 East African Saline Lakes .......................................................................................................... 12 Fish Communities in East African Saline Lakes .......................................................................14 Potential Uses and Value of Saline Lake Fishes ..................................................................... 18 Current Research on Fish Populations of Saline Lakes in the East African Rift Valley ........ 20
منابع مشابه
Rh proteins and NH4(+)-activated Na+-ATPase in the Magadi tilapia (Alcolapia grahami), a 100% ureotelic teleost fish.
The small cichlid fish Alcolapia grahami lives in Lake Magadi, Kenya, one of the most extreme aquatic environments on Earth (pH ~10, carbonate alkalinity ~300 mequiv l(-1)). The Magadi tilapia is the only 100% ureotelic teleost; it normally excretes no ammonia. This is interpreted as an evolutionary adaptation to overcome the near impossibility of sustaining an NH3 diffusion gradient across the...
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The Magadi tilapia, Alcolapia grahami, a small cichlid fish of Lake Magadi, Kenya lives in one of the most challenging aquatic environments on earth, characterized by very high alkalinity, unusual water chemistry, and extreme O2, ROS, and temperature regimes. In contrast to most fishes which live at temperatures substantially lower than the 36-40 °C of mammals and birds, an isolated population ...
متن کاملPhysiological and molecular characterization of urea transport by the gills of the Lake Magadi tilapia (Alcolapia grahami).
The Lake Magadi tilapia (Alcolapia grahami) is an unusual fish, excreting all its nitrogenous waste as urea because of its highly alkaline and buffered aquatic habitat. Here, using both physiological and molecular studies, we describe the mechanism of branchial urea excretion in this species. In vivo, repeated short-interval sampling revealed that urea excretion is continuous. The computed urea...
متن کاملDiscordance between genetic structure and morphological, ecological, and physiological adaptation in Lake Magadi tilapia.
The Magadi tilapia (Alcolapia grahami, formerly Oreochromis alcalicus grahami) is a remarkable example of teleost life in an extreme environment. Typical conditions include water pH=10, titration alkalinity>300 mM, osmolality=525 mOsm, temperatures ranging from 23 degrees to 42 degrees C, and O(2) levels fluctuating diurnally between extreme hyperoxia and anoxia. A number of relatively small ti...
متن کاملMagadi tilapia ecological specialization: filling the early gap in the speciation continuum.
Cichlid fish are well known for their high speciation rates, which are usually accompanied by spectacular and rapid diversification in eco-morphological and secondary sexual traits. This is best illustrated by the famous repeated explosive radiations in the African Great Lakes Tanganyika, Malawi and Victoria, each lake harbouring several hundreds of mostly endemic species. Correspondingly, cich...
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