Gymnosperms are seed producing plants which do not produce any covering surrounding seed. Cycas and Gnetum are two example of Gymnosperms that are respectively considered as primitive and advanced species. In this article, Primitive characters of Cycas and advanced ones of Gnetum will be discussed explicitly. CYCAS Cycas is a …

A domain is the highest taxonomic level of species in biology. In 1977, Woese and his coworkers developed the groundbreaking three-domain system.  They proposed this classification based on differences in the sequences of nucleotides in the cell’s ribosomal RNAs (known as 16S rRNA). They created the first worldwide tree of …

The genes of nuclear chromosome have a significant and key role in the inheritance of almost all traits from generations to generations,but altogether they cannot be considered as the sole vehicle of inheritance because certain experimental evidences suggest the occurance of certain extranuclear genes or DNA molecules in the cytoplasm …