the biogeography of genus linaria was revealed by the available chromosome counts from all over the world. chromosome numbers of 92 taxa of the genus linaria are included in an on-line karyological database. furthermore, information about chromosome numbers taken from 374 literature sources was used in this paper. each database record includes name of taxon, data on chromosome and data on the o...

the present study reports the chromosome number and meiotic behaviour of 14 populationsbelonging to four taxa of anchusa subgenus buglossum gusul. from iran. all populationsshowed the chromosome number 2n= 4x= 32. it is the first meiotic study for a. subg.buglossum. we discuss some habit form and evolutionary aspect in the light of cytogeneticdata. the origin of polyploidy (auto-allopolyploidy)...

Background: Aberrant chromosomes can cause azoospermia but little is known about its molecular mechanism. Our aim is to explore any possible genetic defective to explain a given male infertility. Materials and Methods: An azoopsermic male was identified in a 23 years old male. G-banding and FISH confirmed the karyotype as chromosome insertion (18:7) (q22.1; q36.2q21.11). NGS was performed to an...

Among 17786 karyotyres performed in our center,during 18 years (1357-1375),1300(7.3%) cases of chromosome 21 aberration,including 1284(98.77%) of Down syndrome have been detected.1191 of cases (92.76%) born free trisomy 21:61 cases (4.75%) revealed translocation and 32 cases (2.4%) showed mosaic pattern.among the pateints,59 had robertsonian translocation,2 had translocation between chromosome ...

Background: The maternal age effect for trisomy is well known. However what is less established is whether certain women are more (or less) prone to segregation errors, independent of age. Trisomy arises primarily through maternal meiosis I chromosome segregation errors however the precise mechanism by which these errors occur is unclear. Current dogma attributes the origin of trisomy to malseg...

the karyotype of zagros tooth-carp, aphanius vladykovi (coad) has been investigated byexamining metaphase chromosomes spreads obtained from gill epithelial and kidney cells. the diploidchromosome number of this species was 2n=48. the karyotype consisted of 8 submetacentric and 40subtelocentric chromosomes (8sm+40 st). the arm number (nf) was 28. sex chromosomes werecytologically indistinguishab...

background and objectives: primary amenorrhea is not a disease but a symptom that may result from several quite different causes[nn1] . common hormonal cause of primary amenorrhea includes constitutional delay, hypothalamic –pituitary dysfunction, chronic systemic disease and absent ovarian function. the aim of this study was to estimate the incidence of the chromosomal abnormality referred for...