The salivary gland, gut and thoracic muscle, all of which are polyploid in the adult, have 26% to 35% of DNA as satellite, compared to 47% in the diploid brain.

How many chromosomes are there in each stage of mitosis in Drosophila?

With the exception of sex cells (eggs and sperm), there will be the same number of chromosomes in all cells of the body. If fruit fly skin cells have eight chromosomes then wing cells will also have eight chromosomes. These body (somatic) cells undergo mitosis. Fruit fly somatic cells have eight chromosomes.

In what form does the chromosomes exist in an Undividing cells?

Before replication, one chromosome is composed of one DNA molecule. In replication, the DNA molecule is copied, and the two molecules are known as chromatids.

What is polity and chromosome?

Polytene chromosomes are large chromosomes which have thousands of DNA strands. They provide a high level of function in certain tissues such as salivary glands of insects. Polytene chromosomes were first reported by E.G.Balbiani in 1881.

What is salivary gland chromosome?

Definition of salivary chromosome : one of the very large polytene chromosomal strands made up of many chromatids that are typical of the salivary gland cells of various insects.

Are mitosis cells haploid or diploid?

Mitosis produces two diploid (2n) somatic cells that are genetically identical to each other and the original parent cell, whereas meiosis produces four haploid (n) gametes that are genetically unique from each other and the original parent (germ) cell.

Is meiosis diploid or haploid?

Meiosis involves the division of a diploid (2n) parent cell. The chromosomes are duplicated, but carry out two consecutive divisions. The result is four haploid (n) cells, each with half the number of chromosomes as the parent cell due to the separation of homologous pairs in meiosis I.

What is Chromomere and Chromonemata?

Chromomeres are organized in a discontinuous linear pattern along the condensed chromosomes (pachytene chromosomes) during the prophase stage of meiosis. The linear pattern of chromomeres is linked to the arrangement of genes along the chromosome. Aggregates of chromomeres are known as chromonemata.

How do the salivary glands of Drosophila grow?

The salivary glands of Drosophila and some other insects achieve their growth through an increase in cell mass and volume rather than an increase in the number of cells. After an initial population of salivary gland cells is established during early larval development, cell division ceases.

What is the largest chromosome in Drosophila melanogaster?

The polytene chromosomes are the largest chromosomes available for cytological studies. These chromosomes are clearly seen in the third instar larva of Drosophila melanogaster. The salivary gland chromosomes undergo somatic pairing and endoduplication without separation. This multistranded chromosome contains 1024 chromosomal fibrils.

Why study the development of the salivary gland?

The developing salivary gland thus provides a simple system for studying the control of organelle position and size, cell shape changes, cell migration, tube formation, changes in cell physiology, the transition from euploidy to polyteny, and tissue-specific gene expression. 2. Specification of salivary gland fates

What is the life cycle of a Drosophila?

Polytene Chromosomes in Drosophila The fly, Drosophila melanogaster, is a holometabolous insect with four main stages to its lifecycle: embryo, larva, pupa, adult. As a larva, the organism is primarily concerned with obtaining food for the rapid increase in size characteristic of this stage of development.