At some sites which are designated to become crossovers, a different sequence of events unfolds. The first detectable step in this sequence is... View Article
Meiotic recombination begins when both strands of the DNA double helix are cleaved at many locations by the enzyme Spo11. The exposed DNA 5' ends... View Article
There are two main outcomes - Either a non-crossover event which aids in facilitating homolog pairing, however, it does not produce a lasting... View Article
In the meiotic prophase, homologous chromosomes where each is identified by a sister-chromatid pair—become linked together in preparation... View Article
In multicellular organisms, entry into the meiotic program occurs only in a small population of cells, called the germline, which are the... View Article
Defects in the meiotic chromosome segregation are infrequent in most of the entities however, more frequent in humans, as they can cause gametes... View Article
Although homologs are separated, cohesion between sister-chromatid pairs is maintained at the centromeres throughout the first meiotic division.... View Article
Chiasmata hold homologs together in meiosis I only as the sister-chromatid arms distal to the chiasmata (that is, on the side away from the... View Article
After the meiotic prophase, homolog pairs become bi-oriented on the first meiotic spindle. As each homolog comprises two sister chromatids, there... View Article
The events of the meiotic prophase are accompanied by chromosomal changes that are visible under the microscope. In the early prophase,... View Article
Double-strand breaks are introduced at many instances along the chromosomes, and single-stranded DNA segments developing at these breaks interact... View Article
A. Both are due to a quantitative defect in globulin chain synthesis B. Thalassemia is due to less synthesis of globulin molecules C. Both are... View Article
A) Thalassemia is due to less synthesis of globin molecules B) Both are due to a quantitative defect in globin chain synthesis C) Both are due... View Article
Birds show female heterogamety, i.e. the females have different types of chromosomes and are responsible for sex determination. Males have two... View Article
Yellow/green are the contrasting traits of seed colour and round/wrinkled are the contrasting traits of seed shape of the pea plant. Here yellow... View Article
In the test cross, the dominant phenotype whose genotype is to be determined is test crossed with the recessive phenotype. The ratio of the... View Article
The phenotype of a plant with the genotype Tt would be tall. Here tallness (T) is a dominant trait over dwarfness (t), which is recessive.... View Article
Doctors inject oxytocin to induce labour pain and delivery. Oxytocin is released by the posterior pituitary in response to the foetal ejection... View Article
