Unaffected, I-1 I-2 presumed heterozygote Affected with DMD II-1 П-2| 1-3 п-4 II-5 II-6 Ш-1| Ш-2 ш-з Ш-4 III-5 ш-6| ш-7 ш-8 IV-1 IV-2 IV-3 IV-4 IV-5 IV-6 IV-7 FIGURE 4.10 A human pedigree for Duchenne muscular

What kind of chromosomal mutations is/are produced by unequal crossing over?

What some ways that incomplete penetrance can occur? Give at least two possible ways on why it occurs.

What is heterozygous variant?

In Drosophila, a heterozygous female for the X-linkedrecessive traits a, b, and c was crossed to a male that phenotypically expressed a, b, and c. The offspring occurred inthe following phenotypic ratios.+  b  c                            460a  +  +                           450a  b  c                              32+ + +                              38a  + c                              11+ b +                               9 No other phenotypes were observed.(a) What is the genotypic arrangement of the alleles ofthese genes on the X chromosome of the female?

what are Lethal effects of homozygosity for a deletion

In 1952, an article in the British Medical Journalreported interesting differences in the behavior ofblood plasma obtained from several people who suffered from X-linked recessive hemophilia. Whenmixed together, the cell-free blood plasma from certain combinations of individuals could form clots inthe test tube. For example, the following table showswhether clots could form (+) or not (−) in variouscombinations of plasma from four people withhemophilia:1 and 1 − 2 and 3 +1 and 2 − 2 and 4 +1 and 3 + 3 and 3 −1 and 4 + 3 and 4 −2 and 2 − 4 and 4 −What do these data tell you about the inheritance ofhemophilia in these individuals? Do these data allowyou to exclude any models for the biochemical pathway governing blood clotting?

Two phenotypically unaffected parents produce two children withfamilial Down syndrome. With regard to chromosomes 14 and 21,what are the chromosomal compositions of the parents?

What is the Characteristic pedigree for mitochondrial disease?

Females of wild-type Strain A and males of mutant Strain B, as well as females of mutant Strain B and males of wild-type Strain A, make reciprocal crosses. Explain why reciprocal crosses are needed in genetics experiments involving Drosophila fruit flies.