A study of genetic diversity in Populus nigra subsp. betulifolia in the Upper Severn area of the UK using AFLP markers

A survey of amplified fragment length polymorphism (AFLP) was conducted to examine genetic diversity in 146 individuals of British, native black poplar ( Populus nigra subsp. betulifolia ) and three individuals considered by collectors to be non- betulifolia poplars. Using two primer pairs, a total of 147 bands were detected of which 82 (56%) were polymorphic in at least one individual. Cluster analysis and principal coordinates analysis of the calculated similarity matrix revealed a low level of genetic diversity, although a loose clustering into five groups could be identified, one of which contained the non- betulifolia individuals. Examination of the spatial distribution of the other four groups (all betulifolia ) revealed a general correlation between geographic proximity and genetic similarity. On the basis of the polymorphism observed, it was possible to identify a small number of individual plants which exhibit maximum diversity and might therefore be suitable for inclusion in a replanting programme designed to maintain at least the existing low level of polymorphism observed within British black poplar.     

Synthesis of Haemoglobin Lepore

HAEMOGLOBIN Lepore is a class of haemoglobin variants composed of α-chains and hybrids of δ and β-chains, which can be designated as α₂(δβ)₂. The N-terminal amino-acid sequence of the hybrid chains corresponds to that of δ-chains, while the C-terminal sequence corresponds to that of β-chains. A misplaced synapse of the δ and β gene loci is thought to have occurred during meiosis, followed by a non-homologous cross-over¹. Three types are known which differ in the position of the cross-over: Hb Lepore Hollandia^2,3, Hb Lepore Baltimore⁴ and Hb Lepore Boston (Washington)^5,6.