Evolution of venom Squamata

-



recent research suggests evolutionary origin of venom may exist deep in squamate phylogeny, 60% of squamates placed in hypothetical group called toxicofera. venom has been known in clades caenophidia, anguimorpha, , iguania, , has been shown have evolved single time along these lineages before 3 groups diverged, because lineages share 9 common toxins. fossil record shows divergence between anguimorphs, iguanians, , advanced snakes dates 200 mya late triassic/early jurassic. fossil evidence jurassic.


snake venom has been shown have evolved via process gene encoding normal body protein, typically 1 involved in key regulatory processes or bioactivity, duplicated, , copy selectively expressed in venom gland. previous literature hypothesized venoms modifications of salivary or pancreatic proteins, different toxins have been found have been recruited numerous different protein bodies , diverse functions.


natural selection has driven origination , diversification of toxins counter defenses of prey. once toxins have been recruited venom proteome, form large, multigene families , evolve via birth-and-death model of protein evolution, leads diversification of toxins allows ambush predators ability attack wide range of prey. rapid evolution , diversification thought result of predator–prey evolutionary arms race, both adapting counter other.








Comments

Post a Comment

Popular posts from this blog

Gigantomastia Breast hypertrophy

-
the first recorded case of gigantomastia, diagnosed in 23- or 24-year-old woman, circa 1670. in 1670, physician durston drew illustration of first recorded case of non-gravid gigantomastia; woman died of condition. a painting lam qua of lu-shi, age 42, on april 17, 1848, prior breast reduction surgery. one , extreme case study of gigantomastia dates 1670. patient died 4 months after onset of enlargement. 1 breast removed after woman s death weighed 29 kg (64 lb). on april 17, 1848, 42-year-old woman named lu-shi treated hypertrophy in chinese hospital. treated missionary physician. on december 24, 1849, left breast, measuring 67 cm (26.5 in) in circumference, , weighing 2.7 kg (6 lb), removed in procedure lasting 3 , half minutes. right breast removed 1 month later. measured 61 cm (24 in) in circumference , weighed 2.5 kg (5.5 lb). in 2005, woman reported breasts grew @ puberty nothing c cup in 1 month. when became pregnant first time, b...
Read more

History Conagra Brands

-
the previous conagra brands logo, used until june 2009. in 1971, nebraska consolidated mills changed name conagra , portmanteau of con consolidated , agra, short in english agriculture. 1970s brought company brink of ruin lost money expanding fertilizer, catfish, , pet product industries , commodity speculation wiped out conagra s margins on raw foods. in 1974, c. michael mike harper, experienced food industry executive, took on firm , brought brink of bankruptcy. nonetheless, conagra s business model left vulnerable volatile commodity prices. in response, company set off on two-decade-long buying spree, purchasing on 1 hundred prepared food brands, starting 1980 purchase of banquet foods. moved heavily frozen food business , packaged meat industry, , picked selection of other brands firms rjr nabisco , beatrice foods among others, leveraged buyouts of 1980s resulted in divestiture or breakup of many major american consumer product firms. in 1993 alone purchased $500 million in smal...
Read more

Demographics Union County, Tennessee

-
age pyramid union county at 2000 census, there 17,808 people, 6,742 households , 5,191 families residing in county. population density 80 per square mile (31/km²). there 7,916 housing units @ average density of 35 per square mile (14/km²). racial makeup of county 98.46% white, 0.10% black or african american, 0.23% native american, 0.16% asian, 0.02% pacific islander, 0.17% other races, , 0.86% 2 or more races. 0.79% of population hispanic or latino of race. there 6,742 households of 35.40% had children under age of 18 living them, 62.20% married couples living together, 10.50% had female householder no husband present, , 23.00% non-families. 19.80% of households made of individuals , 7.40% had living alone 65 years of age or older. average household size 2.62 , average family size 2.99. 25.70% of population under age of 18, 8.90% 18 24, 31.00% 25 44, 23.60% 45 64, , 10.80% 65 years of age or older. median age 36 years. every 100 females there 98.80 males. every 100 females age 18 ...
Read more