188 



Chromosome Maps 



A number of genes in the four linkage groups of Drosophila 

 melanogaster are listed in Table 4. With the name of the gene 

 are presented the locus of the gene, the part of the body prin- 

 cipally affected by the gene, and the symbol used to identify the 

 gene. This list is not intended to be complete as only a small 

 percentage of the genes actually discovered is included. Table 

 5 is a similar linkage map for the ten chromosomes of maize. 



TABLE 5 



Some of the Genes Located in Maize with the Name of Each, Its Symbol, 



AND Its Locus 



Chromosome I 

 pericarp color— P 

 25 asynapsis — as 

 52 brachytic plant — br 

 57 fine stripe-l — /i 

 74 anther ear-1 — am 

 101 green-striped-1 — gsi 

 128 brown midrib-2 — bm2 



Chromosome IV 

 defective endosperin-l — dei 



35 gametophyte — Ga 



56 tassel seed-5 — Tsi, 



66 small pollen — sp 



69 lethal ovule — lo 



71 sugary — su 



74 defective endosperm-16 — dcie 

 100 tunicate— ru 

 105 japonica-2 — jo 

 111 glossy seedling-3 — glz 



Chromosome VII 



virescent seedling-5 — v^ 

 14 ramosa ear-1 — roi 

 18 glossy seedling-l — gh 

 28 teopod— Tp 

 34 lojap striping — ij 

 52 brown aleurone-1 — Bni 



Chromosome II 

 liguleless — Ig 

 19 glossy seedling-2 — gh 

 38 plant-color booster — B 

 45 silkless — sk 

 57 floury endosperm^^ 

 63 tassel seed-1 — tsi 



71 virescent seedling-4 — 1;4 



Chromosome V 



aleurone color — 02 

 6 brown midrib-1 — bmi 

 12 brevis height — bv 

 31 red aleurone-l— pri 

 40 yellow stripe-l — ysi 



72 virescent 8eedling-2 — V2 



Chromosome VIII 

 male-sterile-8 — mss 

 18 japonica-1 — ji 



Chromosome X 

 narrow leaf-1 — nli 

 18 golden-1 — gi 

 32 colored aleurone and plant — R 



Chromosome III 

 aleurone color — ai 

 28 nana-1 — nai 

 39 barren stalk-1 — 6a 1 

 56 tassel seed-4 — tSi 

 63 ragged leaf — Rg 

 85 dwarf-1— di 

 103 crinkly leaf-1 — cri 



Chromosome VI 



poljrmitotic — po 



13 yellow endosperm-l — Yi 



41 purple plant color — PI 



51 salmon silk — sm 



61 pigmy— py 



Chromosome IX 



Oknob 



2 yellow green-2 — yg2 

 21 aleurone color — C 

 24 shrunken endosperm — sh 

 39 brown pericarp — bp 

 54 waxy endosperm — wx 

 66 virescent seedling-l — vi 



Other Genetical Methods of Determining Linkage Groups 



The method for determining linkage groups described in the 

 last chapter is the method in almost universal use. Others, how- 

 ever, have been suggested and have been used to a hmited ex- 

 tent. One method, suggested by Muller and Painter, is based 

 upon the frequency with which changes or mutations in genes 

 occur. Another method is based upon crossing over in organisms 

 which have three sets of haploid chromosomes instead of two. 



