Chromosomes

Drosophila Melanogaster, or better known as the common fruit fly, is found all over the world and referred to as the cosmopolitan species (Mitrick, 2010). This fruit fly has three main body parts, which include the head, the thorax, and the abdomen. On males, the bottom half of the abdomen is black, while on the female, each segment of the abdomen is striped black. Drosophila have four main stages to their life cycle. These include: egg, larva, pupa and adult. The eggs small and translucent eggs…

they produce large quantities of progeny. Besides these reasons, this species has more advantages for genetic analyses. While most organisms have a higher chromosome count, D. melanogaster has only four chromosome pairs, three pairs of autosomal chromosomes and one pair of sex chromosomes, making it fairly easy to determine on what chromosome…

disease developing. There are three different forms of genetic testing that can be done. These are gene tests where individual genes or relatively short lengths of DNA or RNA are tested. Another form of testing is chromosomal tests where whole chromosomes or very long lengths of DNA are tested. The last form of testing is biochemical testing, where protein levels or enzyme activities are tested. (FAQ) The DNA or RNA taken for a gene test is taken from a person’s blood, body fluids like saliva,…

the parent cell. Mitosis is the division of the genetic material in the nucleus which is immediately followed by cytokinesis. On the other hand, meiosis occurs in sexually reproducing organisms and this type of cell division reduces the sets of chromosomes from two to one in gametes. Both mitosis and meiosis differ, however, both processes result in daughter cells forming. In the end of mitosis, two daughter cells appear shortly after and have identical DNA like the parent cell. However, in…

permanent change in the sequence of DNA that usually cause harmful effects to the physical body; for the animal being tested this is caused by foreign chemicals of the drug that cause mutations. When this happens the mutation causes changes to the chromosomes which makes the physical appearance of the animal change, this becomes as disadvantage when the animal develops a mutation that may be in favour of the animal e.g. increased…

additional chromosome. Trisomy 13 is a chromosomal disorder that affects either all or a portion of the 13th chromosome. Each person is given a set of chromosomes, one from mom and the other from dad. During embryo development, the 13th chromosome takes on an additional set from either parent. This results in a set of three chromosomes. The severity of the abnormality associated with Trisomy 13 depends on the specific location and percentage of the duplicated cell in the 13th chromosome. …

Daughters born to male carriers will inherit their fathers affected X chromosome and they will also be carriers. Sons born to male carriers will not inherit their fathers X chromosome and furthermore will not be affected by Fragile X. Although the level of these repeats varies for each person, boys seem to have more severe impacts then girls; this is because boys only have one X chromosome whereas girls have 2. The segment which repeats and causes this condition is called the “CGG…

imprinting disorder caused by the failure to express SNRPN (small nuclear ribonucleoprotein-associated polypeptide N) gene product. SNRPN is expressed only on the paternal chromosome 15q11-q13, however, the exact genes responsible for Prader-Willi syndrome haven't been identified. People normally inherit one copy of chromosome 15 from each parent. Some genes are active only on the copy that is inherited from a person's father, the paternal copy. Genomic imprinting causes this parent specific…

It results in the sex chromosome being incomplete and results in an ‘XO’ in the 23rd pair instead of the regular ‘XX’. This results in the birth of a female with Turner’s syndrome – resulting in a short stature, infertility, heart defects and learning disabilities. As Turner’s syndrome is due to an incomplete meiosis division, it is random and not hereditary. This affects 1 in 2000 baby girls. During regular meiosis, in interphase the DNA is replicated once, the chromosomes will find their…

caused by a mutation in the ATP6V1B2 gene on chromosome 8p21 or a mutation in the KCNH1 gene on chromosome 1q32. It affects individuals who are of Eastern Indian ancestry from India and the West Indies and also individuals from European descent. Zimmermann Laband Syndrome is inherited as an autosomal dominant trait, but also may exist as an autosomal recessive trait. This disease is genetic and can only be inherited. Scientist have also found a gene on chromosome three that may cause some cases…