Blunt-end cut
To cleave phospho-diester bonds in the backbone of duplex DNA between the corresponding nucleotide pairs on opposite strands. This cleavage process results in both strands finishing at the same residue, i.e., there are no nucleotide extensions on either strand. a.k.a. flush-end cut.

Blunt-end ligation
Joining (ligation) of the nucleotides that are the ends of two blunt-ended DNA duplex molecules

Bovine somatotrophin
(BST) (also bovine somatotropin) a.k.a. bovine growth hormone this protein is found naturally in cattle, and is the bovine counterpart of human growth hormone, one of the earliest biopharmaceutical products.   It has been cloned, using recombinant DNA technology, expressed in large amounts and marketed as an agricultural product to improve the growth rate and protein: fat ratios in farm cattle, a d to improve milk yield. Its use is banned in some countries

Bovine spongiform encephalopathy
(BSE) a.k.a. mad cow disease. See proteinaceous infectious

Bp
Abbreviation for base pair(s). Double stranded DNA is usually measured in bp rather than nucleotides  (nt)

Bract
A modified leaf that subtends flowers or in may appear to be a petal

Breed Noun
In AnGR, either (i) a sub-specific group of domestic livesstock with definable and identifiable external characteristics that enable it to be separated by visual appraisal from other similarly defined groups within the same species or (ii) a group of domestic livestock for which geographical and/ or cultural separation from phenotypically similar groups has let acceptance of its separate identity. cf breed at risk; breed not at risk; critical breed; critical-maintained breed; endangered-maintained breed. (Source: FAO, 1999)