Question

genetics:

please answer as best you can and explain! this was all the info I was given for this problem so if you think its not enough info please do not attempt!

thank you in advance and ill leave a good rating!

1. A beef cattle breeder wants to produce a herd of cattle with a reduced fat content in the muscles. The breeder has two herds to choose from and has decided to hire YOU, geneticist extraordinaire, to tell her which herd to start with. The information you have on the fat content variabilities is as follows: VARIANCE SOURCES FOR FAT CONTENT o2po28 110 12 029 68 0201 15 OGXE 15 HERDI HERD 2 110 12 2340 35 a) Calculate broad-sense and narrow-sense heritabilities for each herd. b) Explain briefly which herd would be better for a traditional selection scheme of "select the best and cull the rest", and why you chose to use that herd. c) A fly geneticist wants to select for body weight in a fly strain. The original population had a mean body weight of 1.3mg. The parents selected for the study had a mean body weight of 3.Omg. The Fl resulting from these parents had a mean body weight of 2.0mg. 1) what is the heritability of this trait in this population? Is this narrow-sense or broad-sense heritability? Why is this often called "realized heritability?" 2) Suppose the F1 flies are used to produce an F2. Given this heritability, what is the expected mean weight of the F2 flies?

Answer 1

var p = var g + var e

p - phenotype , g - genotype , e - environment

HERD 1 : 110 = var g + 12

var g = 110 - 12

= 98

HERD 2: 110 = var g + 12

var g = 98

a) HERD 1

Broad sense heritibility = variance of genotype / variance of phenotype

= 98 / ( 110)

= 0.89

Narrow sense heritibility = additive genotypic variance / variance of phenotype

= 15 / (110)

= 0.13

HERD 2

Broad sense heritibility = variance of genotype / variance of phenotype

= 98 / 110 = 0.89

Narrow sense heritibility = additive genotypic variance / variance of phenotype

= 35 / 110

= 0.31

b) HERD 1 i recommend because it has low narrow sense heritibility . i.e, it have only low level of resemblance to the parents. So, more variability is present. Enabling to produce much variable new variety.