TLS Online TPP Program

#Question id: 7297


How is the ABC model for floral identity in Arabidopsis similar to the models for homeotic gene function derived from studies in Drosophila?

#Unit 5. Developmental Biology
  1. The key resposnsibility of homeotic genes in both is patterning of dorsal-ventral asymmetry.
  2. In both organisms, one homeotic gene is expressed at the two ends, a second expressed in to domains more central to that of the first and a third expressed more centrally, thus contributing unambiguous identities to all regions of the organism.
  3. In both organisms, homeotic genes interact, so that it is often the combination of genes present that is critical in specifying structure in adult.
  4. The ABC model of Arabidopsis is essentially identical to the Drosophila model for homeotic gene function, in that the Drosophila version of the A gene is abdominal-A, the Drosophila version of the B gene is Abdominal-B, and the Drosophila version of the C gene is Ultrabithorax.

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TLS Online TPP Program

#Question id: 4735

#Unit 8. Inheritance Biology

In corn, three dominant alleles, called A, C, and R, must be present to produce colored seeds. Genotype A/–; C/– ; R/– is colored; all others are colorless. A colored plant AaCCRr is crossed with colorless plant aaCcRr. What proportional of offspring plant with colorless seed?

TLS Online TPP Program

#Question id: 4737

#Unit 8. Inheritance Biology

Two independent pure line varieties having white and green phenotype in their fruit were cross, the all f1 progeny is white fruit. The F2 progeny obtain from selfing show white, yellow and green in ratio of 12:3:1. Which of the following is correct?

TLS Online TPP Program

#Question id: 4738

#Unit 8. Inheritance Biology

Red kernel color in wheat results from the presence of at least one dominant allele of each of two independently segregating genes . Kernels on rr bb plants are white, and the genotypes R— bb and rr B— result in brown kernel color. Suppose that plants of a variety that is true breeding for red kernels are crossed with plants true breeding for white kernels produced F1 were allowed to selfing .what are F2 phenotype ratio ?

TLS Online TPP Program

#Question id: 4739

#Unit 8. Inheritance Biology

Inheritance of leaf variegation in the four-o’clock plant, Mirabilis jalapa. the leaves and shoots of one variety of four-o’clock were variegated, displaying a mixture of green and white splotches. If  Flowers on the variegated branches gave rise to

TLS Online TPP Program

#Question id: 4741

#Unit 8. Inheritance Biology

The F2 progeny from a particular cross exhibit a modified dihybrid ratio of 9 : 7 (instead of 9 : 3 : 3 : 1). What phenotypic ratio would be expected from a testcross of the F1?

TLS Online TPP Program

#Question id: 4742

#Unit 8. Inheritance Biology

In birds, sex is determined by a ZW chromosome scheme. Males are ZZ and females are ZW. A recessive lethal allele that causes death of the embryo is sometimes present on the Z chromosome in pigeons. What would be the sex ratio in the offspring of a cross between a male that is heterozygous for the lethal allele and a normal female?