Casein and lactose concentrations in milk of 31 species are negatively correlated.
Casein and lactose concentrations in milks of various species vary by at least 1-2 orders of magnitude, yet no single species secretes both components at either the high or the low end of the ranges. This pattern of variation could result from evolutionary adaptations in a single secretory mechanism.
D000818:Animals; D005075:Biological Evolution; D002364:Caseins / Q000032:analysis*; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D007785:Lactose / Q000032:analysis*; D008322:Mammals / Q000378:metabolism*; D008321:Mammary Glands, Animal / Q000648:ultrastructure; D008892:Milk / Q000032:analysis* / Q000378:metabolism; D008895:Milk, Human / Q000032:analysis; D013045:Species Specificity
D002364:Caseins; D007785:Lactose