In cucumbers, heart-shaped leaves (h) are recessive to normal leaves (h) and having numerous fruit spines (n) is recessive to having few fruit spines (n). the genes for leaf shape and number of spines are located on the same chromosome; findings from mapping experiments indicate that they are 32.6 m. u. apart. a cucumber plant having heart-shaped leaves and numerous spines is crossed with a plant that is homozygous for normal leaves and few spines. the f1 progeny are then crossed with plants that have heart-shaped leaves and numerous spines (testcross). 5a. create a drawing to indicate the chromosomes, gene arrangements and phenotypes of the f1 parents and the nonrecombinant and recombinant progeny produced from the testcross. (8 points)

In 1959, doctors began using the powerful antibiotic methicillin to treat infections of staphylococcus aureus, but within two years, methicillin-resistant strains of s. aureus (mrsa) appeared. how did the resistant strains of s. aureus emerge? in 1959, doctors began using the powerful antibiotic methicillin to treat infections of staphylococcus aureus, but within two years, methicillin-resistant strains of s. aureus (mrsa) appeared. how did the resistant strains of s. aureus emerge? staphylococcus aureus bacteria that were able to synthesize cell walls using a protein that was not affected by methicillin survived the methicillin treatments and reproduced at higher rates than did other individuals. over time, these resistant individuals became increasingly common. in response to treatment of staphylococcus aureus infections with methicillin, some bacteria began to synthesize cell walls using a protein that was not affected by methicillin. these bacteria survived the methicillin treatments and reproduced at higher rates than did other individuals. over time, these resistant individuals became increasingly common. in response to treatment of staphylococcus aureus infections with methicillin, bacterial populations gradually began to synthesize cell walls using a protein that was not affected by methicillin.