Answer:
B. As the distance between loci increases, some multiple crossovers go undetected such that the relationship between recombination frequency and map distance ceases to be linear.
Explanation:
When calculating recombination frequencies, and hence, map distances, we might notice that these distances are not completely additive. They might vary. <em>For example, let us say that we have three genes, A, B, and C, in that order. </em>We calculated that the <em>distance between A and B equals 5.9</em> MU and that <em>B and C are 19.5 MU apart.</em> According to this, we might say that the <em>total distance between A and C is 25.4 MU (5.9 + 19.5). </em>However, after a<em> two-point calculation between A and C, the value equals 23.7 MU. </em>
The recombination frequency between these two genes located in the extremes and far apart underestimate the actual genetic distances between them because there might occur other crossing-overs that were not detected. This is <em>when calculating the distance between A and C, we probably will not detect the occurrence of a double recombinant between them, and hence, we might sub-estimate the real distance.</em>
The relationship between the actual map distance (number of crossing overs) and the recombination frequency between two loci, is not lineal. The farther apart are the two genes, the worse is the distance estimation.
Explanation:
The study of how plants, animals, and organisms are spread across the globe over time and space is known as biogeography.
Example of biogeography includes the splitting of Pangea (all the Earth's continents were one large landmass).
Answer:
secrete a cytokine that triggers apoptosis
Explanation:
Cytotoxic T cells secrete granzymes and perforins when targeting cells. Additionally they secrete cytokines such as IFN-, TNF-α and TNF-β that act to activate macrophages and help kill infected cells.
Answer:
A chemical reaction is the process in which atoms present in the starting substances rearrange to give new chemical combinations present in the substances formed by the reaction. These starting substances of a chemical reaction are called the reactants, and the new substances that result are called the products.
