(Science: cell biology) giant chromosomes produced by the successive replication of homologous pairs of chromosomes, joined together (synapsed) without chromosome separation or nuclear division. They thus consist of many up to 1000) identical chromosomes (strictly chromatids) running parallel and in strict register.
Which of the following is are the giant chromosome?
Polytene chromosomes or salivary chromosomes are the giant chromosomes discovered by Balbiani (1881) in the salivary glands of Chironomous tantans. Later they were found in the salivary glands and Malpighian tubules) of many insect larvae including Drosophila.
What are Balbiani rings?
Balbiani rings are exceptionally large puffs on the polytene chromosomes in the dipteran Chironomus tentans. These puffs are particularly well suited for studies of the structure of active genes and the synthesis and transport of specific RNA-protein (RNP) particles.
Do humans have giant chromosomes?
Polytene chromosomes are formed when the products of multiple rounds of S-phase remain tightly associated to form one supersized chromosome. … We also note that polytene chromosomes can form in cells that undergo transient nuclear envelope breakdown without subsequent chromosome separation (Cantero et al.
What is the scientific name for cell division?
Mitosis is a process of nuclear division in eukaryotic cells that occurs when a parent cell divides to produce two identical daughter cells. During cell division, mitosis refers specifically to the separation of the duplicated genetic material carried in the nucleus.
What is Endomytosis?
The replication of chromosomes in the absence of cell or nuclear division, resulting in numerous copies within each cell. … Cells in these tissues contain giant chromosomes (see polyteny), each consisting of over a thousand intimately associated, or synapsed, chromatids.
Which is the largest chromosome?
Chromosome 1 is the largest human chromosome, spanning about 249 million DNA building blocks (base pairs) and representing approximately 8 percent of the total DNA in cells.
What is the function of Lampbrush chromosome?
Lampbrush chromosomes are also involved in the production of “masked” mRNAs for early development. The giant granular loops could either be the sites where such mRNAs are packaged or they could be sites where specific alterations of the deoxyribonucleoprotein fiber take place.