The provided question is incomplete as it lacks the combinations of parent as metion in the question, however the complete question is attached as the image.
Answer:
There are two parent combinations that are :
1. heterozygous black Ff cross with heterozygous black Ff
2. heterozygous black Ff cross with white ff
Explanation:
1. in first combination the each parent will produce F and f gametes, as it is shown as Capital F so it will be dominant over f as per the rule. so the cross can be shown as :
F f
F FF Ff
f Ff ff
where, FF are black Ff black and ff white offspring. As there is clearly 3 black offspring over one white spring so the ratio is 3:1 or 75% chances of black and 25% chances of white offspring (phenotype).
2. in second combination there would be F and f gametes for black parent and f and f for white parent, thus the offsprig would be :
F f
f Ff ff
f Ff ff
As, there is two black and two white springs are produced than the ratio would be 2:2 or 50% chances of each white offspring and black offspring (phenotype)
Economics - is the social science that describes the factors that determine the production, distribution and consumption of goods and services
The answer is C because if a doctor only tested new medication on one person then gave it to many other people with the same disease there might have been a mistake and could kill people
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.
