Exam 1: Mendels Principles of Heredity

In corn,three dominant genes are necessary for aleurone colour.The genotype B_D_R_ is coloured.Any homozygous recessive for one gene is colourless.Predict the genotypes and phenotypes of the offspring of the cross BbDdRr × BbDdRr Phenotype: 27 coloured;37 colourless

______ is/are a cross(es)between parents that differ in only one trait.

The phenotypic ratio 2:1 may indicate

In some genetically engineered corn plants,a dominant gene (BT)produces a protein that is lethal to certain flying insect pests that eat the corn plants.It was also found that the pollen could cause death in some flying insects.If the corn plant is heterozygous for BT,what proportion of the pollen would carry the dominant gene?

When both egg and pollen from the same plant produce a zygote,the process is called

Affected individuals in the following pedigree are homozygous for the allele that causes the trait.What are the possible genotypes of persons 1,2,3 and 4?

In codominance,F₁ hybrids show the traits of both parents.

A YY or yy genotype is called heterozygous.

In corn liguleless, (l)is recessive to ligules (L)and a green leaf (G)is dominant to the normal non-green (g).If a plant homozygous for liguleless and green leaves is crossed to one homozygous for non-green with ligules,predict the phenotypes and genotypes of the F₁.Assume independent assortment.

At fertilization,in the mating of dihybrids,four different kinds of eggs can combine with four different kinds of pollen,producing a total of sixteen different genotypes.

During gamete formation,different pairs of alleles on different chromosomes segregate independently of each other.

If an individual has 10 gene pairs,how many different gametes can be formed if three of the gene pairs are homozygous and the remaining seven gene pairs are heterozygous?

Seeds of some lentils are speckled.A true breeding strain with small speckles is crossed with a true breeding strain with large speckles.All of the F1 progeny have both large and small speckles.Which of the following is true?

In Drosophila,forked (fk)bristles are recessive to normal (fk⁺)and glassy eyes (gls)are recessive to normal (gls⁺).If a homozygous wild-type male is mated to a forked-bristled,glassy-eyed female,predict the genotypes and phenotypes of the F₂.Assume independent assortment.

You are out on a nature walk up in the mountains and you find a pretty wildflower in the lower altitude that is short and bushy with small,fragrant,bright purple flowers.In the higher altitude you find what seems to be the same plant,yet it is tall and sparse with larger flowers of the same colour and fragrance.A)Set up an experiment to test the hypothesis that the plants are different due to genetic but not environmental influences.B)Is it possible to tell if both genetic and environmental effects occur?

Calculate the probability of either all-dominant or all-recessive genotypes for the alleles A,B,E,and F in the following cross: AaBbccddEeFf× AaBbCcddEeFf

A _____________ is a cross between an unknown and a homozygous recessive.

A phenotype reflecting a new combination of genes occurring during gamete formation is called