In this problem we will explore some of the many ways that mutations in two different genes can interact to produce different Mendelian ratios. Consider a hypothetical insect species that has red eyes. Imagine mutations in two different unlinked genes that can, in certain combinations, block the formation of red eye pigment yielding mutants with white eyes. In principle, there are two different possible arrangements for two biochemical steps responsible for the formation of red eye pigment. The two genes might act in series such that a mutation in either gene would block the formation of red pigment. Alternatively, the two genes could act in parallel such that mutations in both genes would be required to block the formation of red pigment.

Further complexity arises from the possibility that mutations in either gene that lead to a block in enzymatic activity could be either dominant or recessive. If the crosses between a wild type insect with red eyes and a true breeding white eyed strain with mutations in both genes. Such considerations yield the Pathways in parallel with dominant mutations in both genes, determine the phenotype of the F1 progeny and the expected phenotypic ratio of red to white eyed insects in the F2.

#Question id: 23966

#Unit 8. Inheritance Biology

#Question id: 5734

#Unit 8. Inheritance Biology

Following is heterozygote for inversion?

Following some statement given for above abnormality?

A) There is a less probability of a crossover occurring within inversion region and producing an enviable cross over meiotic product.

B) Chromosomes that have engaged in crossing-over separate in the normal fashion, without the creation of a bridge

C) The crossover produces chromatids that contain duplication and a deletion for different parts of the chromosome results non viable gamete

D) Double cross over within inversion loop will be results all viable gamete of parental and recombinant

#Question id: 5733

#Unit 8. Inheritance Biology

In individuals heterozygous for a chromosome inversion, the homologous chromosomes form a loop in prophase I of meiosis.

Which of the following is effect of inversion?

A. A dicentric and an acentric chromosome in meiosis I as the chiasmata gets terminated when inversion includes centromere  

B. Appearance of deletion and duplication in both the cross over products chromosomes when centromere outside of inversion region  

C. All recombinant gamete are non-viable gametes when single crossing over within inverted region; irrespective to paracentric or pericentic inversion

D. Nonviable gametes are usually produced, resulting in a depression in observed recombination frequencies.

Which of the above statements are correct?

#Question id: 5731

#Unit 8. Inheritance Biology

If an individual is heterozygous for this translocation, the consequence in meiosis will be as follows:

A) Segregation results in a + c in one Gametes and b + d in another gametes, have duplication and deficiency so unable to produce viable offspring

B) Segregation results in a + b in one Gametes and c + d in another gametes, have normal chromosome so all viable offspring produced

C) Segregation results in a + d in one Gametes with normal chromosome and b + c in another gametes contains translocation arrangement, all viable offspring produced

D) Segregation results in a + d in one Gametes with normal chromosome, will produced viable offspring while b + c in another gametes contains translocation arrangement, will produce non viable offspring.

#Question id: 5730

#Unit 8. Inheritance Biology

In a family, father is homozygous dominant (AA) for a gene A and his wife is homozygous for its ressive allele (aa) showing albino phenotype. It was surprising that their child showed the albino phenotype. Which of the following phenomenon can explain the phenotype?

#Question id: 5729

#Unit 8. Inheritance Biology

One chromosome in a plant has the sequence A B C D E F, and another has the sequence M N O P Q R. A reciprocal translocation between these chromosomes produced the following arrangement: A B C P Q R on one chromosome and M N O D E F on the other. If an individual is heterozygous for this translocation, the consequence in meiosis will be as follows:    

A. The two normal chromosomes and-two translocated chromosomes pair separately

B. Half of gametes produced from this meiosis are non-viable as they have deletions and duplications

C. In one of the cross configurations called "horizontal segregation" all gametes having normal or translocated chromosomes will not survive

D. The gametes having normal chromosomes only survive while all gametes having translocated chromosomes are non-viable, hence the translocations are used as crossover suppressors

Which of the following combinations best describes the meiotic consequences for the translocation described above?