Free Chromosome Essays and Papers

eukaryotic chromosome duplication describes a highly coordinated process by which temporally regulated replicon clusters are sequentially activated and subsequently united to form two semi-conserved copies of the genome. Replicon clusters, or replication domains, are comprised of individual replication units that are synchronously activated at predetermined points during S phase. Bi-directional replication within each replicon is initiated at periodic AT-rich origins along each chromosome. Origins

The mechanisms responsible for the origin and maintenance of large non-recombining regions on sex chromosomes have been mostly studied in plants and animals, but the recent discovery of similar features on the fungal chromosomes carrying mating type genes in several species may shed new light on this phenomenon (Fraser et al. 2004). Sex chromosomes in plants and animals have evolved from an autosomal pair by the expansion of the non-recombining region around complementary genes determining sex-specific

born with two sets of chromosomes. 23 chromosomes are from the mother and 23 chromosomes from the father, creating a total of 46 chromosomes for the child. But for some children born today, they are born with chromosome abnormalities. Chromosome abnormalities involve sex chromosomes and are gender specific (O’Neil). With today’s technology and past studies, we are able to determine chromosome abnormalities and the syndromes that are formed by these abnormalities. Chromosome abnormalities happen

Chromosome silencing has led to a breakthrough in the world of Down syndrome, though it has proven to have multiple moral viewpoints that have come to be associated with it. Down syndrome is one of the most frequently occurring genetic disorders in the human population. Statistically, the chance of delivering a child with Down syndrome rises as the mother grows older. “Researchers now realize that older mothers have more babies with DS because the frequency of meiotic nondisjunction increases in

(Martins, 1999). The theory established chromosomes as the carriers of hereditary information (genes). It also implied that chromosomes (and not genes) undergo segregation and independent assortment as proposed by Gregor Johann Medel (1865-1866) in his Laws of Inheritance. A chromosome can contain more than one gene(s). Although the contemporary scholars were highly skeptical of this idea, Thomas Hunt Morgan (1915), showed linear arrangement of genes in chromosomes providing a convincing evidence for

Y chromosome, the smallest chromosome of the karyotpe, is one of the two sex chromosomes. In 1905, Nettie Stevens identified that Y chromosome is a sex-determining chromosome, while conducting one study of the mealworm Tenebrio molitor. He also proposed that chromosomes always existed in pairs. In 1890 Hermann Henking discovered that Y chromosome was the pair of the X chromosome. All chromosomes normally appear to take on a well defined shape during mitosis when seen under microscope. This shape

Can Two Y Genes Replace the Y chromosome in Mice? The Y chromosome is important in any kind of reproduction because it determines if you’re going to be a male or female. The article claims that live mouse descendants can be created using germ cells from males with the Y chromosome to two genes. The SRY gene is called the sex determining region because it has instructions to make a transcription factor and develops as a male. The Y chromosome gene is required to drive mouse sperm cells to cause mitosis

X and Y Chromosomes are the ones at fault in the end. Male and Female, one has XX chromosomes the other has XY. Both getting assigned roles with their sex. Steinbeck known author challenged literature and gender roles in 502 pages in a novel called The Grapes of Wrath. “…women came out of the house to stand beside their men-to feel whether this time the men would break” (Steinbeck 3). In the beginning of The Grapes of Wrath, Steinbeck describes the terrible fate the country folk face during the

half the number of chromosomes of the parent cell which are called haploids. Meiosis produces our sex cells or gametes which are (eggs in females and sperm in males). Meiosis can be divided into nine stages. These are divided between the first time the cell divides (meiosis I) and the second time it divides (meiosis II): Meiosis I 1. Interphase: First, the DNA in the cell is copied resulting in two identical full sets of chromosomes.

end structure. The fusion of two small, ape chromosomes thought to have fused end-to-end, forming the single large human chromosome 2. It is claimed that human chromosome 2 contains two key regions in its area. The very first region is thought to be the actual head-to-head fusion of telomeres. The second key region supposedly represents a vague non-functional centromere that was put “out of business” following the fusion of telomeres. For each chromosome, one functional centromere is needed for good