erodium (geranaiceae) species are distributed in different habitats of iran. some species are of medicinal importance while some are well known weeds. there are no chromosome counts for erdoium species of iran. chromosome numbers are given for six taxa of erodium (geraniaceae) from iran: e. cicutarium (2n=36), e. ciconium(2n=18), e. malacoides (2n=20), e. moschatum (2n=20), e. neuradifolium (2n...

background: chromosomal disorders are the most common cause of first trimester spontaneous abortion. among the human chromosomes, chromosome no.9 was the most common structural chromosomal variant and it is not thought to be of any functional importance, which often considers as a normal variation in structural polymorphisms, nevertheless there are some studies which claim that there is an asso...

Chromosomal interchanges are of primary interest because of the opportunities they offer for the study of chromosome behavior and crossing over. The great volume of work which has already been done on crossing over and on translocations but still lack of understanding among the graduates students. Hence, continue discussions and question still to be made on this terminology. This paper gives th...

Cellular processes that rely on knowledge of molecular behavior are difficult for students to comprehend. For example, thorough understanding of meiosis requires students to integrate several complex concepts related to chromosome structure and function. Using a grounded theory approach, we have unified classroom observations, assessment data, and in-depth interviews under the theory of knowled...

Regulation of stem cell (SC) proliferation is central to tissue homoeostasis, injury repair, and cancer development. Accumulation of replication errors in SCs is limited by either infrequent division and/or by chromosome sorting to retain preferentially the oldest 'immortal' DNA strand. The frequency of SC divisions and the chromosome-sorting phenomenon are difficult to examine accurately with ...

Most nematodes have XO male/XX female sex determination. C. elegans is anomalous, having XX hermaphrodites rather than females. The hermaphrodite condition appears to result from the modification of a basic male/female sex-determination system, which permits both spermatogenesis and oogenesis to occur within a female soma. This modification is achieved by a germ-line-specific control acting at ...

Sex chromosomes are particularly interesting regions of the genome for both molecular genetics and evolutionary studies; yet, for most species, we lack basic information, such as the gene order along the chromosome. Because they lack recombination, Y-linked genes cannot be mapped genetically, leaving physical mapping as the only option for establishing the extent of synteny and homology with th...