Broad sense heritability vs Narrow sense heritability
Heritability in broad sense and narrow sense
Heritability in broad sense (H2) is calculated using the following formula :
H2 = Sg2/Sp2
Therefore, H2 simply gives a measure of the proportion of phenotypic variance which is due to genotype. However, this does not tell us what proportion of an individual’s phenotype is due to genotype. Moreover, H2 depends on the population in which it is measured and also depends on the set of environments in which the population was grown. For instance in a genotypically homogeneous population (e.g. homozygous parents or F1 hybrids between them), Sg2 = 0 and therefore H2 = 0. It does not mean that genes do not control the phenotype, but no part of the variation can be ascribed to genetic variation. Similarly lack of heterogeneity in environment may lead to a high estimate of H2, but it does not mean that the trait is insensitive to all environments.
Since H2 can not tell us how will a particular trait behave in a particular environment, its utility is limited. In view of this, animal and plant breeders often prefer to estimate heritability in narrow sense (h2), which is based on the knowledge about gene action. For this purpose genetic variance (Sg2) is partitioned into additive genetic variance (Sa2) and dominance genetic variance (Sd2). If A and a are two alleles at a locus controlling a quantitative trait, the Sa2 is associated with the average effect of substitution of A for a in a homozygote (aa →AA) and Sd2is associated with partial dominance of A over a in heterozygotes. Once Sa2is calculated from given data, Sd2can be calculated as follows (The details of methods for computations of Sa2 and Sd2are beyond the scope of this section and the reader is advised to consult a book on Biometrical Genetics for further details) :
Sd2= Sg2- Sa2.
The heritability in narrow sense (h2) is used as a measure of relative proportion of Sa2 as follows :
h2 = Sa2/ Sp2 (as against H2 = Sg2/ Sp2)
The usefulness of this partitioning of genetic variance lies in the prediction about the effect of selective breeding. Greater is the value of h2, better are the chances that the selected individuals will maintain their superiority over the population as a whole. This kind of assurance and confidence is not available when we use H2 (heritability in broad sense). Further, if h2 is high, the selection will bring about an improvement, but if h2 is low it means that Sd2 should be high and heterozygotes will be superior to homozygotes and heterosis breeding should be preferred as done in maize.
#SelectionBreeding #populationGenetics #NarrowSenseHeritability #heritability #breeding #natureVsNurture #nature #nurture #psychology #genes #calculatingHeritability #variance #heritabilityCrashCourse #heritabilityPsychology #heritabilityCalculation #heritabilityEquation #HeritabilityEstimation #heritabilityApPsycology #natureVsNurtureDebate #heritabilityPsycology #natureVsNurtureCrashCourse #natureVsNurturePersonality #NikolaysGeneticsLessons
1 view
59
16
4 months ago 00:04:43 1
Arogya - Queen of the Damned feat. Chris Harms (Lord Of The Lost) (Official Music Video)
4 months ago 00:05:31 1
Victor Ruiz - The Ritual at Ultra Miami 2024
4 months ago 00:03:31 1
Jah Tung - Digital Steppa [Conscious Sounds Mix]
4 months ago 00:01:47 1
Keep a close watch on patients with the Philips wearable biosensor
4 months ago 00:35:46 1
Barefoot Euphoria: Ashiatsu Massage for the Deepest Relaxation and Relief of Muscle Tension
4 months ago 00:12:38 3
JIB LEAGUE || S02 E02.3 Official Broadcast
5 months ago 00:12:21 1
2023 Mercedes Maybach S680 - Big Luxury in Every Sense
5 months ago 00:03:46 1
Igorrr - Parpaing (OFFICIAL VIDEO)
5 months ago 00:03:39 1
Paramore - Burning Down the House (Official Visualizer)
5 months ago 00:59:37 1
BBC - The Fantastic Mr Feynman
5 months ago 00:04:22 1
PUBLIC SERVICE BROADCASTING - GAGARIN
5 months ago 00:06:16 1
CERN People - TAU TROUBLE
5 months ago 00:08:49 10
The Nature of the Sixth Sense Collection - Spring Hare in Marquetry
5 months ago 00:04:12 1
The 1975 - Oh Caroline (Official Live Performance) | Vevo
5 months ago 00:20:16 7
Small BIRDS 8K ULTRA HD with Names and Sounds
6 months ago 00:06:15 1
ROTTING CHRIST-For A Voice Like Thunder-(Official Lyric Video)
6 months ago 00:07:36 4
Fabian Krooss, Harry Charles - Tied in Knots (Original Mix) [Melodic 2024 / A Tribe Called Kotori]
6 months ago 01:26:48 1
Sphera @ Boom Festival 2023 [full set movie]
6 months ago 00:02:35 1
SZA - Kill Bill (Lyrics)
6 months ago 00:04:13 1
Boost Testosterone With Best Pelvic Floor Exercises
6 months ago 00:03:39 1
Paramore - Burning Down the House (Behind The Scenes)
6 months ago 00:26:13 1
“ MEN IN CRISIS: McCARTHY VS. WELCH ” 1954 ARMY-MCCARTHY HEARINGS & MCCARTHY ERA DOCUMENTARY XD37154
6 months ago 00:08:08 1
🔥 Самые Крутые Кастом Мотоциклы (Часть 1) 😲!
6 months ago 00:06:00 1
1960 Suburban Life Presented By The American Government. A Dream Lifestyle