Question: List and explain the three mechanisms that contribute to genetic variation.
Step-by-step explanation:
In meiosis genetic diversity arises due to the shuffling of chromosomes during meiosis. Three mechanisms that contribute to genetic variation include the independent assortment of chromosomes, crossing over, and random fertilization.
Crossing Over
Crossing over involves the exchange of segments of DNA between homologous chromosomes during prophase I.
Random Orientation
When homologous chromosomes line up in metaphase I, their orientation towards the opposing poles is random. The orientation of each bivalent occurs independently, meaning different combinations of maternal or paternal chromosomes can be inherited when bivalents separate in anaphase I.
Random Fertilization
The fusion of two haploid gametes results in the formation of a diploid zygote. This zygote can then divide by mitosis and differentiate to form a developing embryo.
Remember that the meiosis results in genetically distinct gametes, random fertilization by egg and sperm will always generate different zygotes.
Answer: we can conclude that the correct answer is:
Crossing Over
Crossing over involves the exchange of segments of DNA between homologous chromosomes during prophase I
Random Orientation
The random line up of homologous chromosome pairs at the cell equator. When homologous chromosomes line up in metaphase I, their orientation towards the opposing poles is random.
Random Fertilization: since meiosis results in genetically distinct gametes, random fertilization by egg and sperm will always generate different zygotes.