Answer:
12:3:1
Explanation:
<em>The typical F2 ratio in cases of dominant epistasis is 12:3:1.</em>
<u>The epistasis is a form of gene interaction in which an allele in one locus interacts with and modifies the effects of alleles in another locus</u>. There are different types of epistasis depending on the type of alleles that are interacting. These include:
- Dominant/simple epistasis: Here, a dominant allele on one locus suppresses the expression of both alleles on another locus irrespective of whether they are dominant or recessive. Instead of the Mendelian dihybrid F2 ratio of 9:3:3:1, what is obtained is 12:3:1. Examples of this type of gene interaction are found in seed coat color in barley, skin color in mice, etc.
- Other types of epistasis include <em>recessive epistasis (9:3:4), dominant inhibitory epistasis (13:3), duplicate recessive epistasis (9:7), duplicate dominant epistasis (15:1), and polymeric gene interaction (9:6:1).</em>
Answer:
<u>Biofilms are</u> defined as complex communities of microorganisms that grow embedded in a self-produced polymeric organic matrix and adhered to a living or inert surface, and that can present a single microbial species or a range of different species
Explanation:
The bacteria that form the biofilm are in what is called sessile form, exhibiting a phenotype different from those of the same cells in unicellular or free form (planktonic form) with respect to the growth rate and gene transcription (Donlan, 2002 ).
<u>
The formation</u> of biofilms is an adaptive strategy of microorganisms, since growth in biofilm offers four important advantages: (I) protects microorganisms from the action of adverse agents, (II) increases the availability of nutrients for their growth, (III) facilitates the use of water, reducing the possibility of dehydration and (IV) enables the transfer of genetic material (DNA). All of these circumstances can increase your survival capabilities. As a consequence, <u>the usual methods of disinfection or the use of antibiotics are often ineffective against biofilm bacteria</u>.
In addition to the risk of contamination, the development of biofilms can interfere with different processes and cause damage to the equipment. In drinking water systems the formation of biofilms can obstruct the pipes reducing their speed and transport capacity causing an increase in energy consumption. The formation of biofilm in heat exchangers and cooling towers can reduce heat transfer and as a consequence its efficiency in the process. The formation of persistent biofilms on metal surfaces can cause corrosion due to acid production by bacteria.
House sparrows in the northern part of North America are larger than those found in the southern regions. The possible mechanism of microevolution is more likely to be responsible for this is natural selection. The answer would be letter B.
