Answer:
Molecular genetic approaches to the study of plant metabolism can be traced back to the isolation of the first cDNA encoding a plant enzyme (Bedbrook et al., 1980), the use of the Agrobacterium Ti plasmid to introduce foreign DNA into plant cells (Hernalsteens et al., 1980) and the establishment of routine plant transformation systems (Bevan, 1984; Horsch et al., 1985). It became possible to express foreign genes in plants and potentially to overexpress plant genes using cDNAs linked to strong promoters, with the aim of modifying metabolism. However, the discovery of the antisense phenomenon of plant gene silencing (van der Krol et al., 1988; Smith et al., 1988), and subsequently co‐suppression (Napoli et al., 1990; van der Krol et al., 1990), provided the most powerful and widely‐used methods for investigating the roles of specific enzymes in metabolism and plant growth. The antisense or co‐supression of gene expression, collectively known as post‐transcriptional gene silencing (PTGS), has been particularly versatile and powerful in studies of plant metabolism. With such molecular tools in place, plant metabolism became accessible to investigation and manipulation through genetic modification and dramatic progress was made in subsequent years (Stitt and Sonnewald, 1995; Herbers and Sonnewald, 1996), particularly in studies of solanaceous species (Frommer and Sonnewald, 1995).
Hox genes are also called Homeotic genes. In which they act as dictators on specific areas of an organism's body on when or where it should be developed. When these genes are overactivated or inactivated it may cause genetic disorders.
Diploblasty is a state of the blastula in which there are two essential germ layers: the ectoderm and endoderm. Diploblastic living beings are life forms which create from such a blastula and incorporate cnidaria and Ctenophora, earlier assembled together in the phylum Coelenterata, yet later comprehension of their disparities brought about their being put in discrete phyla.
To answer the above:
Diploblastic animals have ectoderm and an endoderm as well as radial symmetry.
Your answer is c<span>erebellum; cerebral cortex.</span>
Answer:
In the mid-1800s, over-hunting of Northern Elephant Seals reduced their population size to fewer than 40 individuals. However, the population has since rebounded to over 100,000 animals. The population went through a _<u>bottle neck event (genetic drift)</u>_, which makes it more susceptible to _<u>developing a genetic disease</u>_.
Explanation:
Genetic drift is the random change that occurs in the allelic frequency of a population through generations. The magnitude of this change is inversely related to the size of the original population. These changes produced by genetic drift accumulate in time. Eventually, some alleles get lost, while some others might set. Genetic drift affects a population and reduces its size dramatically due to a disaster or pressure-bottleneck effect- or because of a population split -founder effect-
. The bottleneck effect most likely affects smaller populations.
In the exposed example, extensive hunting acted as a pressure that reduced the number of Northern elephant seals to fewer than 100. This population experienced one or many generations of small size since these animals were affected by hunting. As the survivors did not have the whole genetic pool of the original population, the <em>population size might have recovered to a current population size of 100,000 individuals</em><em>,</em><em> but the genetic pool might have not</em><em>.</em> When the small population increases in size, it will have a genetically different composition from the original one. In these situations,<em> there is a reduced genetic variability, with a possibility of developing a peculiar allelic component</em>. If the <em>survivors in the population carried or developed a mutation, probably this mutation passed from generation to generation</em>. It will involve <em>more individuals each time and</em><em> increase the probability of developing a genetic disease.</em>
