In 1965 a faulty study was performed, which suggested that the XYY karyotype was associated with violent antisocial criminal behavior. The study was later disproven, as there is no association between an additional Y chromosome and abnormal behavior. Explain how this karyotype could arise in someone by mentioning the sex of the affected person, the identity of the parent (mother or father) in which the non-disjunction occurred, and the specific meiotic division during which non-disjunction took place.

explain the Nondisjunction during second meiotic division

Why are the karyotypes with extra or missing X chromosomes, Turners syndrome, klinefelters syndrrome and triple x, relatively harmless ?

In fruit flies, chromosomal crossing over does not occur in meiosis in males, whereas crossing over does occur in meiosis in females. In fruit flies that are heterozygous at many genes (i.e. many maternal and paternal versions of the genes differ), at what stage would cells no longer be heterozygous for any gene during the process of meiosis? a)After the second meiotic division in males, and after the first meiotic division in females. b)After the second meiotic division in both males and females. c)After the first meiotic division in both males and females. d)After the first meiotic division in males, and after the second meiotic division in females.

Identify each of the following statements as true or false. The chromosomes in B are the result of mitosis from the chromosomes in A.  Alleles B and C are more likely to segregate together during anaphase I than alleles B and A.  The two white chromosomes in B are homologous chromosomes.  Genes A, B, and C are linked genes.  A trihybrid Punnett square can be used to determine the possible combinations of the F1 generation.

A D. melanogaster male is homozygous for a translocation between chromosomes 2 and 3.  This fly is otherwise wild-type.  This male is crossed to a female fly that is homozygous for normal chromosome order and is homozygous for dumpy wings (dy), a recessive on chromosome 2 and sepia eyes (se), a recessive on  chromosome 3. A male progeny from the above cross is test-crossed to a female fly that is homozygous for dy and se.  What progeny phenotypes and frequencies are expected from this second cross? Answer choices 1/2 wild-type and 1/2 dumpy and sepia 1/4 wild-type, 1/4 dumpy, 1/4 sepia, 1/4 dumpy and sepia All dumpy and sepia                       2/3 wild-type, 1/3 dumpy and sepia 9/16 wild-type, 3/16 dumpy, 3/16 sepia, 1/16 dumpy and sepia

Please list and briefly describe the steps occuring on each side of the following: