Embryonic development is where most of the attention is concentrated, but there is also a great deal of interest in how various adult structures develop into the pupa, mostly focused on the development of the compound eye, but also on the wings, legs, and other organs” (Manning 2008). D. melanogaster is a great example to understand Mendel’s law of inheritance. Mendel’s Law of Segregation states that all individuals carry two alleles, which can be dominant or recessive. Mendel’s second law, the Law of Independent Assortment, states that genes assort independently of each other (Cummings 2010). In this species, mutations can be targeted to specific genes.
January 11, 2014 Pgs: 250-257 AP Biology Meiosis and Sexual reproduction 1. Differentiate between haploid and diploid cells. Give one example of each cell. The difference between a haploid and a diploid cell is that a diploid is a cell that has two sets of chromosomes. On the other hand, a haploid cell contains only one set of chromosomes.
In order to perform this experiment first virgin flies had to be attained by separating all adults from the stock vials and quickly separating the newly hatched egg larva into male and female containers. Throughout the experiment males and females were split into groups of red eyes, white eyes, ebony etc. in order to attain the proper crosses. The results from this lab show roughly the proper ratios one would achieve when using the chi-square method to determine the genetics of these fruit-flies. Introduction: Drosophila are a tiny fly about 3mm in length and are most commonly found around spoiled fruit.
Harvest of Egg Cells For mammals, which are the animals that scientists most commonly clone, egg cells are microscopic. Scientists gather these cells from adult females. Since the success rate for animal cloning is still very low, they need many of these egg cells. All egg cells used in this step are haploid, meaning they have not been fertilized with sperm. They thus contain only half of the genetic material common to the animal's cells and have not yet undergone any development.
Additionally, the DNA of mitochondria and chloroplasts are different from that of the eukaryotic cell in which they are found. As Margulis predicted, both types of organelles include DNA that is like that of prokaryotes- circular, not linear. The DNA of these organelles evolves independently and at a different rate from the nuclear DNA of the eukaryotic cell. Mitochondria arise from pre-existing mitochondria and chloroplasts arise from pre-existing chloroplasts (not manufactures through the direction of nuclear genes). A fairly simple piece of evidence for the endosymbiotic hypothesis is the fact that both mitochondria and chloroplasts have double phospholipid bilayers.
The DNA is linear and forms into chromosomes before cell division. In eukaryotes the normal process of cell division is called mitosis, with exception of gamates. In mitosis the chromosomes are copied and divided equally
This law states that a pair of traits separates so that each gamete receives only one copy of the trait. As research continued, Oscar Hartwig proposed the idea of meiosis (Wood, 2009), during which a sperm and egg each give half of their genetic material (traits) to their offspring. Each gamete after meiosis has half of their genetic make up from paternal and maternal gametes. Law of Independent Assortment: The Law of Independent Assortment states that different gene pairs assort independently in gamete formation (Griffiths, Wessler, Lewontin & Carroll, 2008). When Mendel only experimented with one trait (monohybrid cross), the result was always a 3:1 ratio between the dominant and recessive trait.
Each parent has a gene pair in each cell for each trait studied. The F1 from a cross of two pure lines contains one allele for the dominant phenotype and one for the recessive phenotype. These two alleles comprise the gene pair. One member of the gene pair segregates into a gamete, thus each gamete only carries one member of the gene pair. Gametes unite at random and irrespective of the other gene pairs involved.
Genetics 1. Gametes have half the numbers of ___________ that body cells have. (chromosomes) 2. What are the 2 cell divisions that meiosis, diploid cells undergo? (meiosis I and II) 3. Who led the groundwork for genetics?
Matched sets of chromosomes provides you with two copies of each gene. Dramactic differences in body and brain cells are due to which genes are “expressed” or activated. Genes make up less than 2% of human DNA. pg 352 8. Define each of the following terms: Conception- when chromosomes of the biological mother and father combine to form a single cell –the fertilized egg or zygote.