what is the actaual experiment or conclusion made by t.h mporgan on experimenting fruit fly

 

Asked by khanklashan319 | 9th Mar, 2018, 04:28: AM

Expert Answer:

  • Thomas Hunt Morgan used Drosophila melanogaster (fruit flies) to show how sexual reproduction gave rise to variations. 
  • Morgan conducted dihybrid cross between yellow-bodied, white-eyed females and brown-bodied, red-eyed males. Interestingly, the self-crossing of F1 generation gave an F2 generation but not in the ratio of 9:3:3:1. The result showed a deviation from Mendel’s dihybrid cross.
  • Morgan observed that while crossing a set of characteristics, two genes did not segregate as per Mendel’s law. If two genes were present on the same chromosome, the probability of getting a parental combination was much higher in the next generation as compared to the non-parental combination. This physical association of genes was termed as linkage.
  • In addition, he noted that the probability recombination is dependent on how strong the linkage is. In other words, though there is a link between two genes on chromosomes, genes may or may not be tightly linked. Some genes have strong linkage giving less chance of recombination while another linkage of genes is weak (loosely linked) giving a higher chance of recombination.
  • Once the linked genes were discovered, the frequency of linked genes also influenced the appearance of traits in the next generation. 
 

Answered by Sheetal Kolte | 9th Mar, 2018, 11:24: AM