The points of crossing over in meiosis appear as
The points of crossing over in meiosis appear as
The correct option is C Chiasmata
During prophase I of meiosis I, homologous chromosomes pair and exchange DNA (homologous recombination). This often results in chromosomal crossover which is nothing but the exchange of genetic material (occurs when matching regions on matching chromosomes break and then reconnect to the other chromosome) between homologous chromosomes. It occurs during a process called “synapsis” which occurs before the synaptonemal complex develops. For an example, in the figure given, the letters A, B, and C represent genes found at particular spots on the chromosome, with A, B and C and a, b, and c letters representing different forms, or alleles, of each gene. The DNA is broken at the same spot on each homologue—here, between genes B and C—and reconnected in a criss-cross pattern so that the homologues exchange part of their DNA. A protein structure called the synaptonemal complex holds the homologues together along much of their length and helps in the process that may last from hours to days. The association of the two chromosomes is called bivalent, and because there are four chromatids involved it is also called a tetrad. The points of attachment are called chiasmata (singular of which is called chiasma). These spots where crossovers happen are random and the new combinations of DNA created are a significant source of genetic variation, and result in combinations of alleles that are not only new but also may be beneficial. Hence,, the correct answer is option C.
During prophase I of meiosis I, homologous chromosomes pair and exchange DNA (homologous recombination). This often results in chromosomal crossover which is nothing but the exchange of genetic material (occurs when matching regions on matching chromosomes break and then reconnect to the other chromosome) between homologous chromosomes. It occurs during a process called “synapsis” which occurs before the synaptonemal complex develops. For an example, in the figure given, the letters A, B, and C represent genes found at particular spots on the chromosome, with A, B and C and a, b, and c letters representing different forms, or alleles, of each gene. The DNA is broken at the same spot on each homologue—here, between genes B and C—and reconnected in a criss-cross pattern so that the homologues exchange part of their DNA. A protein structure called the synaptonemal complex holds the homologues together along much of their length and helps in the process that may last from hours to days. The association of the two chromosomes is called bivalent, and because there are four chromatids involved it is also called a tetrad. The points of attachment are called chiasmata (singular of which is called chiasma). These spots where crossovers happen are random and the new combinations of DNA created are a significant source of genetic variation, and result in combinations of alleles that are not only new but also may be beneficial. Hence,, the correct answer is option C.
