Leakey, Richard
The son of renowned anthropologists Louis and Mary Leakey, Richard continued their work an early hominids from 1964 until the 1980s, making a number of significant fossil finds in the Lake Turkana area and serving as Director of the National Museum of Kenya. Later the devoted his energies to conservation and politics.

Levine, Michael
Professor of Genetics and Development in the Molecular and Cell Biology Department at University of  California, Berkeley. Discoverer (with Bill McGinnis) of homeobox sequences in the homeotic genes Antennapedia and Ultrabithorax while a postdoctoral researcher with Walter Gehring at the University of Basel, Switzerland.

Lek
An area of ground divided into territories that are defended by males for the purpose of displaying to potential mates during the breeding season. This form of mating behaviour is known as lekking, and occurs in various bird species (for example the peacock) and also in some mammals. The dominant males occupy the territories at the centre of the lek, where they are most likely to attract and mate with visiting females. The outer territories are occupied by subordinate, males who have less mating success.

Over successive breeding seasons, younger subordinate males tend to gradually displace older individuals from most desirable territories and become dominant themselves. The lek territories do not contain resources of value to the female; such as food or nesting materials, although males of some species may build structures such as bowers that form part of their display.

Lethal recessive
The case in which inheriting two recessive alleles of a gene causes the death of the organism.

Leucine zipper
A structural motif found in members of one family of transcription factor, characterized by leucine residues occurring in the polypeptide every seventh amino acid. Leucine zippers - ­on two polypeptides appear to interact to form a dimer that binds to DNA.