>Yesterdays addition of the LA Times contained an article entitled--Facts
>About Bras, Breasts and Cancer.  The very first bit of info stated<The breast
>is actually a modified sweat gland; breast milk is a modification of sweat.>
> What am I missing???

It was thought for many years that the first lacteal glands were modified
from sweat glands, but that is no longer thought to be the case, according
to mammalian evolutionary ecologists.  For fascinating research on this
topic, see :

Blackburn, D.G.  1993  Lactation: Historical patterns and potential for
manipulation.  Journal of Dairy Science 76:3195-3212.

Blackburn, D.G., V. Hayssen, and C.J. Murphy  1989  The origins of lactation
and the evolution of milk: A review with new hypotheses.  Mammal Review
19(1):1-26.

Research into the evolutionary origin of the mammary gland suggests that
mammary glands evolved before viviparity (life birth), and the original
purpose of early proto-lacteal secretions was to kill microbes in the nest
and on the surface of eggs.  Ingestion of the secretions by the young, once
they had hatched, helped establish optimal intestinal flora in the young.
Only later did the nutritional and immunological functions of lactation
evolve, including the evolution of alpha-lactalbumin from lysozyme, allowing
the synthesis of lactose.

Regardless, breast milk comes from modified blood, ultimately, which comes
from modified (digested) food -- why the big concern?  And note that while
all mammals lactate (by definition), not all mammals sweat.

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Katherine A. Dettwyler, Ph.D.                         email: [log in to unmask]
Anthropology Department                               phone: (409) 845-5256
Texas A&M University                                    fax: (409) 845-4070
College Station, TX  77843-4352