Answer:
The correct answer is- 4:0
Explanation:
Marfan syndrome is a genetic problem which affects the connective tissue in the body. The trait for this disease is autosomal dominant which means even one abnormal copy of this gene in the offspring or individual is sufficient to cause this syndrome.
Let S is the allele that is dominant for this syndrome and s is recessive. So if a cross between homozygous dominant(SS) and heterozygous individual (Ss) occurs than all the offspring would have this syndrome.
S s
S SS Ss
S SS Ss
Therefore all 4 offspring would have at least one dominant allele which is sufficient to cause this syndrome. So the phenotype ratio would be 4:0.
Answer:
haemoglobin
Explanation:
Inside the air sacs, oxygen moves across paper-thin walls to tiny blood vessels called capillaries and into your blood. A protein called haemoglobin in the red blood cells then carries the oxygen around your body
Answer:
Which type of selection tends to increase genetic variation? A. Disruptive selection B. Directional selection C. Stabilizing selection
The Answer is option A (Disruptive selection)
Explanation:
Selection can either shift the mean value of a trait, reduce the trait's variation, or increase its variation.
Genetic variation which allows natural selection to increase or decrease frequency of alleles already in the population is a source of phenotypic variation as it refers to differences in all the hereditary information of members of the same species.
Disruptive Selection is important in maintaining variation and initiating speciation as it Increases Variation by favoring alleles corresponding to more extreme phenotypes. But for it to occur, the mean phenotype has to experience the lowest fitness. Disruptive selection affects the frequency distributions of alleles and genotypes within a population.
Disruptive selection is based on the variance of a trait in a population as it increases genetic variance by equalizing the frequencies of existing alleles at polymorphic loci (a genetic loci with two or more alleles). Disruptive selection maintains and may even increase variation in natural populations by favoring extreme phenotypes, individuals with extreme values for a trait have greater reproductive success than individuals with intermediate values.
Answer: <u>Guanine
</u>
According to Chargaff's rule, the base pairing in the DNA and RNA is fixed. Adenine always pairs with Thymine in DNA and Uracil in RNA. Guanine pairs up with cytosine. This complementary base pairing is universal and constant. That's why amounts are also equal. It means if cytosine is 20% in any DNA sample, then amount of guanine would be 20% as well.
