Answer:
Crossing over and random alignment are the events of meiosis-I that add new gene combinations to the gametes. Random fusion of male and female gametes is called random fertilization.
Explanation:
During the pachytene stage of meiosis-I, part of the chromatids of each of the homologous chromosomes of a bivalent is broken apart and exchanged. This exchange of the genetic material between the members of a bivalent is called crossing over. The recombinant chromatids formed by crossing over have new allele combinations that were otherwise not present in the parental chromatids.
During metaphase I, the homologous pairs are aligned at the cell's equator in a random manner. This means that either the paternal or maternal chromosome of a pair may face one or the other pole of the cell. The arrangement of chromosomes during metaphase-I determines whether the paternal or maternal chromosome of each pair would be distributed to one or the other pole of the cell. This random segregation creates new gene combinations in gametes.
All the gametes have equal chances of getting fused with a gamete from the opposite gender. This is called random fertilization and further adds variations.
Chromosome 7 may lose an end piece resulting in Williams syndrome, which is an example of a chromosomal deletion.
<h3>What is a chromosomal deletion?</h3>
A chromosomal deletion can be defined as a chromosome rearregement due to the loss of a fragment of the sequence of one chromosome, which leads to the loss of genetic material.
In conclusion, Chromosome 7 may lose an end piece resulting in Williams syndrome, which is an example of a chromosomal deletion.
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Oncogenes are most like the gas pedal on a car, while tumor suppressor genes are most like the brakes on a car. Oncogenes and tumor suppressor genes are mutated in cancer cells.
Oncogenes are genes overexpressed in cells in which they should not be expressed, thereby leading to cancer.
Some examples of oncogenes are growth factors such as, for example, the Platelet-derived growth factor (PDGF) or Epidermal growth factor (EGF).
Conversely, tumor suppressor genes are genes that act to regulate cell division and replication, thereby their inactivation also leads to cancer.
A well-known example of a tumor suppressor gene is the p53 gene that acts to control cell division and apoptosis (programmed cell death).
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I think the best answer would be A. since the number of prairie dogs decreased from the picture on the left to the picture on the right. Hope this helped :p
The answer to the given question above would be BLOOD GROUP ANTIGENS. The term that describes the <span>various protein markers located in the plasma membrane of a red blood cell is called the blood group antigens. Hope this answers your question. Have a great day ahead!</span>
