- F1 = 1/2 Cch (agouti coat); 1/2 chch (albino coat) >> 1:1 phenotypic ratio
Punnett square:
ch ch
C Cch Cch
ch chch chch
Explanation:
A heterozygous individual is an individual who has two different gene variants (i.e., alleles) at a particular <em>locus</em>. In this case, individuals having the "agouti coat" trait are heterozygous carrying both 'C' and 'ch' alleles. On the other hand, a homo-zygous individual has the same allele at a given <em>locus</em> (here, the 'chch' genotype associated with the albino phenotype). Therefore, as observed in the Punnett Square above, when a heterozygous parent is crossed with a homo-zygous recessive parent for a single gene, alleles segregate in the gametes of both parents so an expected 1:1 phenotypic ratio will be observed.
When lactose is not present, what happens to E. coli is that the genes that produce the enzymes needed to break down lactose are not expressed. The correct answer is B.
A.) Pollen are well preserved in the sediment layers because they are highly resistant to decay.
B.) Other indicators that can be used to determine past climates are through the analysis of the width of tree rings and the coral reefs formed underwater.
