B chromosomes are found in many plants and animals and are small non-vital chromosomes mostly consisting of heterochromatin. B chromosomes have few genes and often cause a small fitness cost to their host, making them “selfish” genetic elements.
What is Plant B chromosome?
Background. Supernumerary B chromosomes (Bs) are a major source of intraspecific variation in nuclear DNA amounts in numerous species of plants. They favour large genomes, and create polymorphisms for DNA variation in natural populations.
Who discovered B chromosome?
B chromosomes have been a subject of interest since they were first discovered in the plant bug insect Metapodius, by Wilson in 1906, 1907 [214, 215].
Do humans have B chromosomes?
Small supernumerary marker chromosomes (sSMC) and B-chromosomes represent a heterogeneous collection of chromosomes added to the typical karyotype, and which are both small in size. … However, up to now no B-chromosomes were described in human.
Where is B chromosome found?
B chromosomes are a heterogeneous class of chromosomes found in the nucleus and also are called accessory or supernumerary chromosomes.
What is meant by Euploidy?
Euploidy is a chromosomal variation that involves the entire set of chromosomes in a cell or an organism. … In allopolyploidy, the additional set of chromosomes comes from another species (i.e. from two or more diverged taxa). The cell or the organism in allopolyploidy state is referred to as allopolyploid.
Do fungi have chromosomes?
Fungal core genomes are contained on “A chromosomes”. Supernumerary chromosomes of fungi are specialized “B chromosomes”. Some fungal B chromosomes are “pathogenicity” chromosomes.
What is genetic basis of male sterility?
The discussion of male infertility focuses on genetic factors impairing spermatogenesis and includes numerical chromosomal anomalies such as Klinefelter syndrome, structural chromosomal anomalies such as Y-chromosome microdeletions, certain single gene mutations, syndromic diseases, and epigenetic mutations.