Genetics Answers

The frequency- deoendent selection, as seen in the case of thraot color in the bloated sided lizards tend to:

a. elimante rare alleles and favor whitchever allele is intialling most frequent

b. produce random changes in allele frecuencies

c. maintain two or more phenotypes in a population

d. lead to heterozygous advantage

e. stimulate new mutations

miRNAs are relatively short, on the order of 21-23 nucleotides, they only bind to mRNAs that are a perfect complementary match to the entire length of the miRNA.

A. TRUE

B. FALSE

What are 3 parts of dna nucleotide

what is the complementary DNA strand that is created from the template 3’ GATCAAAATGT during replication

A fruit fly that heterozygous for gray body with vestigial wings (b+ b+ vg+ vg) is mated with one that is true-breeding for black body with normal wings (b b+ vg vg). The genes for body color and wing structure are on the same chromosome. From previous research you know that they are 19 map units apart.


What are the possible offspring that could come from this cross? Label the offspring parental or recombinant.





What is the phenotypic ratio you would expect if the genes were on separate chromosomes?





What is the phenotypic ratio you would expect knowing that they are only 19 units apart

In our population the incidence of polyposis of the large intestine is 1:8,000. The disorder is determined by the autosomal dominant allele. What is the frequency of disease-causing allele in the population?

Assume that congenital dislocation of the lumbar joint is dependent upon the action of a dominant allele

with 25% penetrance (the frequency with which a dominant or homozygous recessive gene manifests itself

in the phenotype of an individual). Frequency of the disorder is 6:10,000. State the number of homozygous

individuals for the recessive allele.

In a cross of AaBb x AaBb, what fraction of the offspring can be expected to express one of the two dominant alleles, but not both?

The following is a hypothetical situation. Assume that the presence and color of hair in a breed of dog is controlled by 2 separate genes. The first gene

controls the presence or absence of hair. Individuals who are homozygous recessive have hair, while those with at least one dominant allele are naked/hairless.

The second gene for hair color produces either blond, brown, or black hair, with those that are homozygous for one allele having blond hair, those who are

homozygous for the other allele having black hair, and the heterozygous individuals being brown-haired.

Show the offspring be for the following cross:

A hairless male is crossed with a brown-haired female. The male had a black-haired mother and a hairless father with blond-haired genes

Write an account on the components and regulation of gene expression in lac

(lactose) operon with the help of clear and well labelled diagram.