Two chromosomes have the ff. order of genes: Normal Abnormal A B C centromere DEFGHI A B G F E D centromere C H I (a) Does the abnormal chromosome have a pericentric or paracentric inversion? Why? (b) Draw a sketch to show how these two chromosomes would pair during synapsis, showing all four strands. In your sketch, assume crossing over has occurred between genes E and F. Illustrate the germ cells produced at the end of Meiosis II and describe these germ cells.

An inversion heterozygote has the following inverted chromosome: Centromere ca a a A B CD JI HGF E, KL M Inverted region If a crossover occurred between genes H and I on one inverted and one normal chromosome, what would be the sequence of the dicentric chromosome before completion of metaphase I? A Cen B C D EFGHIJKL Cen M A Cen B C D JIHGFEKLM Cen JIH G F E Cen A Cen B C D JIHGFEDC B Cen A MLKEFGHIJKLM

8.18 Irradiatioh of Drosophila sperm produces transloca- tions between the X chromosome and autosomes, between the Y chromosome and autosomes, and between different autosomes. Translotations between the X and Y chromosomes are not produced. Explain the absence of X-Y translocations. The birth of this child prompted the Dentons' physician to order a chromosome study of parents and child. The results of the study are shown in the accompanying fig- ure. Chromosome banding was done, and all chromo- somes were normal in these individuals, except some copies of number 6 and number 12. The number-6 and number-12 chromosomes of mother, father, and child are shown in the figure (the number 6 chromosomes are the larger pair): Child Mrs. Denton Mr. Denton a. Does either parent have an abnormal karyotype? If so, which parent has it, and what is the nature of the abnormality? b. How did the child's karyotype arise? (What pairing and segregation events took place in the parents?) e. Why is the child…

Considering the following chromosome which is represented as a series of genes on each arm separated by the centromere. Describe the type of mutation required to produce each of the mutant chromosomes below.   ABCDEFG*HIJKLMN

During a practical, a group of biology students are tasked to study the cell cycle of an insect. This insect has the karyotype 2n=6, with genotype Ff Gg Hh KK. The students must draw a cell at the end of telophase of mitosis, using red lines for maternal chromosomes, blue lines for paternal chromosomes and black dots to represent centromeres. The drawing provided by the students is shown below. kt a) Identify three mistakes the students made when producing this diagram. In your answer only refer to elements already present in the figure. b) This fly is used in a testcross. What is the probability of producing a fly with genotype ff Gg hh Kk?

Part A Diagram A represents a chromosomal inversion event. A, B, C, D, E, F, are chromosomal loci. Represents a centromere. Diagram B shows a crossing over event between non-sister chromatids (darker vs. lighter lines) during meiosis I. A A Which of the following represents a recombinant chromosome resulting from the cross-over event shown in diagram B? E F MARK ALL THE ANSWES THAT APPLY. Inversion A E C B B EEEE

Rice has a chromosome number of 2n = 24. If different aneuploids are available in rice, identifythe specific aneuploidy that shows the following chromosomal configurations at diakinesis ormetaphase I. Also provide the formula and chromosome number of the different aneuploids. Complete the table. Chromosome configuration at diakinesis or metaphase I Specific Type of Aneuploidy Formula (e.g. 2n+1) Chromosome number (2n=24) Types of gametes n, n+1, n+2, n-1, n-2) a. 1 III + 11 II         b. 1 IV + 11 II         c. 1 I + 11 II         d. 11 II         e. 2 I + 10 II

Through the sentences used on the right (choose the appropriate sentence on the right over the appropriate sentence on the left)

A young couple is planning to have children. Knowing that there have been a substantial number of stillbirths, miscarriages, and fertility problems on the husband’s side of the family, they see a genetic counselor. A chromosome analysis reveals that, whereas the woman has a normal karyotype, the man possesses only 45 chromosomes and is a carrier of a Robertsonian translocation between chromosomes 22 and 13. Q. What types of zygotes will develop when each of gametes produced by the man fuses with a normal gamete produced by the woman?

Diploid Number of chromosomes, Sex Chromosomes, (+/- whole) Chromosome (+/- partial) e.g. 47, XY, +14 = male with trisomy of chromosome 14 e.g. 46, XX, 1q+ = female with a partial increase to the length of the long arm of chromosome 1 (partial increases or decreases to a single chromosome still have the same diploid number) What is the notation for the following case A boy having Down syndrome