During metaphase the X-shape structure is called a metaphase chromosome. In this highly condensed form chromosomes are easiest to distinguish and study. Cited 13 Views 2, Annotations Open annotations.
In most animals, including many vertebrates, the unfertilized egg is asymmetrical, with different regions of cytoplasm containing different sets of mRNA and protein molecules discussed in Chapter Morgan had quite different objections to the Mendelian and chromosome theories.
Meiosis II closely resembles mitosis.
Morganall of a rather dogmatic turn of mind. They stimulate the newly arriving primordial germ cells to develop along a pathway that produces sperm. In this way, they develop characteristics more like those of single cells.
These include the structures of the male reproductive tract, such as the prostate and seminal vesicles, which develop from another duct, called the Wolffian duct system.
The fitness peaks in free-living cells being different from that of the multi-cellular organisms is not unexpected. This is the haploid number. Retrieved 13 July Trends in Microbiology. This includes two sex chromosomes: two X chromosomes for females and one X and one Y chromosome for males.
Specialized chromosomes determine gender.