Explanation:
Xenopus laevis is allotetraploid: it has 2 sets of homologous chromosomes originally from one species and 2 sets of homologous chromosomes originally from another species, making a total of 4 sets of chromosomes. During meiosis, every chromosome has another homologous one with which it can pair, producing viable gametes that have the complete genetic information of the species.
Mules, however, are allodiploid: they have one set of chromosomes from a donkey and another set from a horse, making a total of 2 sets of chromosmes. But those two sets are not homologous, so during meiosis the chromosomes can't pair and the gametes will have errors that make them inviable, making mules sterile
A Peptide bond is formed between two molecules
Example: when Carboxyl group and amino group form its releasing a water molecule. (H2O) well i hope this help i did my research c:
The question is incomplete as it does not have the options which have been provided in the attached file.
Explanation:
1. Dura mater: the dura mater is the most superficial layer which is characterized by the folds. The dura mater forms the walls between the hemisphere of the brain that is between right and left halves of the cerebellum. The structure present in the dura mater is tentorium cerebelli and super sagittal sinus.
2. Pia mater: the deepest layer present which is adhered to the tissues of the brain. The cortical gyri blood vesicle are superficial to the pia mater.
3. Arachnoid mater: the middle layer which is characterised by transparent and gelatin-like appearance.
A substance that has a specific shape and volume changes to a substance that has a specific volume is the statement that best describes this change in question. The correct option among all the options that are given in the question is the third option. I hope the answer helps you.
Answer:
C) Through genomic imprinting, methylation regulates expression of the paternal copy of the gene in the brain.
Explanation:
The pattern of gene expression wherein either paternal or maternal gene is expressed in specific cells while the other one is prevented from expression is known as genomic imprinting.
In the given example, the maternal copy of the gene on chromosome 15 is expressed in brain cells while its paternal copy is not expressed in these cells. Hence, the pattern of expression of this gene is regulated through genome imprinting. One of the mechanism is methylation of cytidine residues of CpG islands of the DNA that are more frequently present within promoters of the genes.
When the cytidine residues of these sequences are methylated into 5-methylcytidine, the transcription factors do not bind to these promoters preventing the expression of these genes.
Hence, methylation of cytidine residue in CpG islands of the promoters of the gene present on chromosome 15 could have silenced its expression in brain cells.
