Recessive Gene
A gene which will be expressed only if there are 2 identical copies or, for a male, if one, copy is present on the X chromosome.

Reciprocal Cross
Two crosses, in which the genotype of the female in the first cross is the same as the genotype of the male in the second cross, and vice versa.
2. A cross with the phenotype of each sex reversed as compared with the original cross; made to test the role of parental sex on inheritance patterns.

Recombinant DNA Technology
Procedure used to join together DNA segments in a cell-free System (an environment outside a cell or organism). Under appropriate conditions, a recombinant DNA molecule can enter a cell and replicate there, either autonomously or after it has become integrated into a cellular chromosome.

Reciprocal Translocation
The transfer or exchange of part of two different chromosomes to each other. (ie. Long arm of chromosome # 8 and #10 switch places).
2. When a pair of chromosomes exchange exactly the same length and ar a of DNA. Results in a shuffling of genes.

Recognition Species Concept
A concept of species according to which a species is a set of organisms that recognize one another as potential mates; they have a shared mate recognition system. Compare with biological species concept, cladistic species concept, ecological species concept, and phenetic species concept.

Recombinant
The new individuals arising as a result of recombination.