80 



FAMILY STUDIES IN BUILD. 



Comment. — In this family both parents are of fleshy build and all the 

 children are, likewise, of fleshy build (R : Thr-2). 



Mating 3. Other Very Fleshy x Very Fleshy Matings. (Table XV.) 



There are 7 instances of this type of mating. These are sum- 

 marized in table XV, Appendix. An examination of this table shows 

 that in all families with 2 or more offspring one or more of them are 

 obese. There is no case of slender offspring, though 12 out of 30, or 

 two-fifths, are of medium build and only 10, or one-third of all, are 

 very fleshy. This indicates the presence of recessive factors in the 

 very fleshy parents. It suggests further that there are two or more 

 pairs of factors that must be present to produce very fleshy children. 

 Assuming that there are two factors and that both parents are 



m 



E 



15 



RWfa 



oil lorge we!! proportioned 



Fig. 33. — Pedigree chart showing distribution of build in the Thr-1, 2 families. 



heterozygous for one of them, we should expect very fleshy, fleshy, 

 and medium offspring in about the proportions of 25 : 50 : 25, which 

 distribution is not very close to the actual proportions of 40 : 27 : 33. 

 On the assumption of 3 pairs of factors, we might expect 17 : 32 : 49 

 respectively from a 4 X 5 factor mating. Or the 4X4 factor mating 

 would give on one hypothesis 31 (S + M) : 38 : 31, which is closest 

 of all. All of these very fleshy parents are heterozygous. 



Table XV shows also that when all grandparents are know r n there 

 is always one on each side who is at least of grade 36. 



The contrast between the families of table II and table XV is this: 

 In table II, of the 20 grandparents 40 per cent are slender or very 

 slender. In table XV of 20 grandparents only 30 per cent are fleshy, 



