Answer:
Recessive lethal genes can code for either dominant or recessive traits, but they do not actually cause death unless an organism carries two copies of the lethal allele. Examples of human diseases caused by recessive lethal alleles include cystic fibrosis, sickle-cell anaemia, and achondroplasia.
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Answer:
The correct answer will be option-formation of heterochromatin
Explanation:
Methylation of DNA is the epigenetic mechanism which controls the expression of a gene by adding a methyl group to the cytosine bases in eukaryotic DNA.
The methylation of DNA converts the cytosine residues to the 5-methylcytosine catalysed by DNA methyltransferase enzyme. This results in the silencing of the gene and transcription get switched off.
Studies have shown that DNA methylation is involved in the formation and maintenance of the heterochromatin structure which is the condensed form of the chromatin in which transcription is switched off.
Thus, the formation of heterochromatin is the correct answer.
Answer:
a. shorten
Explanation:
Inability or failure for joints to move through their entire range of motion is caused by constrictions. These constrictions often results when the excess adipose tissues that surrounds the muscles and ligaments are not in required adequate proportion. These constrictions can be caused by ageing, fatigue, muscular diseases etc. As a result of these constriction in the joints, let say for example, the knee joint, the muscle and ligaments tends to shorten in length.
