In files the character vestigial wings (v) is autosomal recessive to normal wing
ID: 81809 • Letter: I
Question
In files the character vestigial wings (v) is autosomal recessive to normal wings (V). White eyes (w) is X-linked recessive to red eyes (W). Male and female flies are crossed. In the F1 following results are obtained: Males 1/2 white eyed vestigial 1/2 white eyed normal wings Females 1/2 red eyed vestigial 1/2 red eyed normal wings What was the genotype of the parents for wing length? What was the genotype of the male and female parents for eye color? Mary and her brother Paul are healthy siblings. Mary and her husband Mike have a healthy girl and Mary is pregnant. They learn that Mary and Paul's mother has just had a son by second marriage, and the boy has Duchenne muscular dystrophy. (DMD is X-linked recessive). Mike is completely normal and there is no history of DMD in Mike's family What is the probability that Mary's unborn baby will have DMD? Normal eye color in flies is red. Mutant flies have brown eye color. Similarly, normal wing length is long. Mutants have short wings. A true breeding female with eyes and short wings is crossed with a true breeding male with red eyes and long wings. In the F1 the female flies are red eyed and long winged. The male flies are red eyed and short winged. F1 males are crossed to F1 females Both sexes of F2 progeny flies have phenotypes as shown: 30 red eyes long wings 30 red eyes short wings 10 brown eyes long wings 10 brown eyes short wings Describe the Genotype of the male and female parents. Deduce the inheritance of each Phenotype.Explanation / Answer
Question 2.
Answer:
Explanation:
Xm= DMD allele
X= normal allele
Mary’s mom is = XmX
XY x XmX
XXm, XmY, XY, XX
There is ½ chances that Mary could be a carrier.
In an X linked recessive inheritance, two copies of a disease allele on the X chromosome are required for an individual with two X chromosomes (a female) to be affected with an X-linked recessive disease.
For a carrier female, with each pregnancy there is a one in two (50%) chance her sons will inherit the disease allele and a one in two (50%) chance her daughters will be carriers.
For May and mike to have a DMAD offspring it has to be a boy
May is ½ chance of being a carrier
There is ½ chance of being a baby boy
There is ½ chance that that baby boy being affected by DMD