10  REM ****  HP TIME-SHARED BASIC PROGRAM LIBRARY  *******************
20  REM
30  REM            GAMGN:  PROCESS OF GAMETOGENSIS
40  REM
50  REM            36302  (A833)  REV A -- 10/71
60  REM
70  REM ****  CONTRIBUTED PROGRAM  ************************************
80  REM  GAMGU--COPYRIGHT 1970-- POLYTECHNIC INSTITUTE OF BROOKLYN
90  REM THIS PROGRAM DEVELOPED BY R. COOPERMAN--JOHN GLENN HIGH SCHOOL
100  REM  REVISED BY C.LOSIK  7-9-70
110  REM  ALL INPUTS ARE TEMPORARY
120  PRINT "THE FOLLOWING DIAGRAMS ARE REPRESENTATIONS OF PRIMARY SEX"
130  PRINT "CELLS. CHROMOSOMES ARE REPRESENTED BY LETTERS."
140  PRINT 
150  PRINT "PRIMARY SPERMATOCYTE          PRIMARY OOCYTE"
160  PRINT "     ----------                ----------"
170  PRINT "     ( A1 A2  )                ( A3 A4  )"
180  PRINT "     (        )                (        )"
190  PRINT "     ( B1 B2  )                ( B3 B4  )"
200  PRINT "     ----------                ----------"
210  PRINT 
220  LET Y=0
230  PRINT "BY TYPING IN A NUMBER,WHAT IS THE DIPLOID NUMBER OF"
240  PRINT "CHROMOSOMES FOR THIS ORGANISM";
250  INPUT C
260  IF C=4 THEN 330
270  PRINT 
280  PRINT " ARE YOU SURE THAT YOU UNDERSTAND WHAT IS MEANT BY DIPLOID"
290  PRINT "AND HAPLOID?"
300  IF Y=1 THEN 1210
310  LET Y=Y+1
320  GOTO 230
330  PRINT 
340  PRINT "SO YOU SEE THAT A1 + A2, FOR EXAMPLE, ARE PAIRS OF HOMOLOGOUS"
350  PRINT "CHROMOSOMES. IT IS ESSENTIAL THAT AFTER FERTILIZATION, IF THE"
360  PRINT "DIPLOID CONDITION IS TO BE RETAINED THAT WE HAVE SOME MEANS OF"
370  PRINT "PLACING ONLY ONE A AND ONE B CHROMOSOME IN THE SPERM AND ONLY"
380  PRINT "ONE A AND ONE B CHROMOSOME IN THE EGG. THIS INVOLVES MEIOSIS."
390  PRINT 
400  PRINT "LOOK AT THE PRIMARY SPERMATOCYTE ABOVE."
410  PRINT "DURING THE FIRST STAGE OF MEIOSIS, THE MALE SEX CELL"
420  PRINT "SHOULD APPEAR AS IT IS IN ONE OF THE FOLLOWING DIAGRAMS."
430  PRINT 
440  PRINT "     1           2           3           4           5"
450  PRINT "----------  ----------  ----------  ----------  ----------"
460  PRINT "( A1A1   )  ( A1  A2 )  (    A   )  (  A1 A2 )  (        )"
470  PRINT "(   A2A2 )  (        )  (        )  (        )  (        )"
480  PRINT "( B1B1   )  (        )  (        )  (        )  (        )"
490  PRINT "(   B2B2 )  ( B1  B2 )  (    B   )  (        )  (  B1 B2 )"
500  PRINT "----------  ----------  ----------  ----------  ----------"
510  LET X=0
520  PRINT 
530  PRINT "WHICH DIAGRAM MOST CLOSELY REPRESENTS THIS MEIOTIC STAGE ";
540  INPUT D
550  IF D=1 THEN 620
560  PRINT 
570  PRINT "YOUR REASONING IS FAULTY."
580  PRINT "DO YOU RECALL THAT A TETRAD IS FORMED?"
590  IF X=2 THEN 1210
600  LET X=X+1
610  GOTO 530
620  PRINT 
630  PRINT "O.K., NOW WE CAN MOVE ALONG. MEIOTIC DIVISION OCCURS AND"
640  PRINT "WE GET TWO SECONDARY SPERMATOCYTES FROM EACH PRIMARY"
650  PRINT "SPERMATOCYTE AND ONE SECONDARY OOCYTE FROM EACH PRIMARY "
660  PRINT "OOCYTE. EACH SPERMATOCYTE CONTAINS THE FOLLOWING CHROMOSOMES:"
670  PRINT "A1 A2, B1 B2.    EACH OOCYTE HAS  A3 A4, B3 B4."
680  PRINT 
690  PRINT "THE REASON WHY ONLY ONE OOCYTE IS PRODUCED IS:"
700  PRINT 
710  PRINT "     1)THE OOCYTE DOES NOT UNDERGO DIVISION."
720  PRINT "     2)THE OOCYTE DIVIDES AFTER FERTILIZATION."
730  PRINT "     3)A POLAR BODY IS FORMED."
740  PRINT "     4)THERE IS AN ERROR IN THE COMPUTER."
750  PRINT 
760  PRINT "WHICH NUMBER WOULD REPRESENT THE CORRECT ANSWER";
770  INPUT E
780  PRINT 
790  IF E=3 THEN 830
800  PRINT "STOP GUESSING. THERE IS A PERFECTLY GOOD EXPLANATION WHICH"
810  PRINT "HAS A VITAL FUNCTION."
820  GOTO 750
830  PRINT "CORRECT.     NOW LET'S MOVE TO THE FINAL STAGE IN WHICH"
840  PRINT "WE WILL END UP WITH 4 MONOPLOID(HAPLOID) SPERM--1)A1B1"
850  PRINT "2)A2B2  3)A1B2  4)A2B1  AND ONE OVUM--1)A3B3 OR  2)A4B4"
860  PRINT "OR  3)A3B4  OR  4)A4B3"
870  PRINT 
880  PRINT "WHAT IS THE POSSIBILITY THAT THE OFFSPRING WILL HAVE"
890  PRINT "THE SAME CHROMOSOMAL COMPOSITION AS THE FATHER?"
900  PRINT "PRINT ONE OF THE FOLLOWING NUMBERS."
910  PRINT "     1)50 CHANCE   2)NO CHANCE   3)100 CHANCE"
920  PRINT "     4)YOU CAN'T TELL FROM THE INFORMATION GIVEN"
930  INPUT F
940  IF F=2 THEN 980
950  PRINT "YOU COULDN'T BE MORE WRONG. LOOK AT ALL THE CELLS AGAIN AND"
960  PRINT "COMPARE ALL POSSIBILITIES."
970  GOTO 930
980  PRINT "GOOD THINKING."
990  PRINT "I HOPE YOU HAVE A FAIRLY GOOD IDEA OF SEVERAL PRINCIPLES"
1000  PRINT "INVOLVED, PARTICULARLY RANDOM ASSORTMENT."
1010  PRINT 
1020  PRINT "NOW LET'S SEE IF WE CAN USE THESE IDEAS TO DETERMINE WHAT"
1030  PRINT "OCCURS IN A POPULATION. WE WILL USE AS OUR ORGANISM THE FRUIT"
1040  PRINT "FLY, DROSOPHILA, WHICH HAS 8 AS THE DIPLOID NUMBER OF"
1050  PRINT "CHROMOSOMES.  THE FOLLOWING WILL REPRESENT CERTAIN CONDITIONS"
1060  PRINT "IN FRUIT FLIES :"
1070  PRINT 
1080  PRINT "NORMAL WING-RED EYE=A1A2, B1B2, C1C2, D1D2"
1090  PRINT "NORMAL WING-WHITE EYE=A1A2, B2B2, C1C2, D1D2"
1100  PRINT "VESTIGIAL WING=A1A1, B1B2, C1C2, D1D2"
1110  PRINT "LETHAL GENE=A1A2, B1B2, C1C1, D1D2"
1120  PRINT 
1130  PRINT "SUPPOSE WE CROSS THE NORMAL RED EYED WITH THE NORMAL"
1140  PRINT "EYED FRUIT FLY. WHAT COULD THE OFFSPRING LOOK LIKE? LOOK AT"
1150  PRINT "THE GENOTYPES CAREFULLY AND SEE IF YOU CAN PICK OUT THE"
1160  PRINT "DIFFERENT GENE COMBINATIONS. THEN MAKE ALL POSSIBLE CROSSES."
1170  PRINT "AT A LATER DATE, WE WILL SEE HOW I, THE COMPUTER, CAN"
1180  PRINT "SOLVE THIS PROBLEM FOR YOU."
1190  PRINT "BUT FIRST, TAKE THIS SHEET BACK TO YOUR SEATS AND WORK ON IT."
1200  STOP 
1210  PRINT "     YOU'RE JUST GUESSING. I DON'T HAVE TIME TO FOOL"
1220  PRINT "AROUND. TAKE THIS SHEET OUT AND STUDY IT; THEN SEE YOUR"
1230  PRINT "TEACHER BEFORE YOU COME BACK TO ME."
1240  REM NEXT PROGRAM NAME IS DROS** 
1250  END 
