PPT-LINKAGE AND CHROMOSOME MAPPNG

Prepared by RAKESH CHOUDHARY MScAGRI GENETICS AND PLANT BREEDING WELCOME Linkage and Chromosome Mapping Linkage and Chromosome Mapping Genetic linkage was first discovered by the . A) Alleles at different loci are independent. B) Alleles at different loci are physically close to each other and on the same chromosome. C) Alternate alleles at the same locus are not independent. D) Alleles at different loci are not independent. The Big Epigenetic Event. Males – 46,XY. Females – 46,XX. Compensate for gene dosage, all mammals inactivate extra X chromosome. Discovered by Mary Lyon. Lyon, M.F., 1961. Gene action in X-chromosome of the mouse (. HORT6033. Molecular . Plant . B. reeding. Instructor: Ainong . Shi. HORT6033 web site: . http://comp.uark.edu/~ashi/MB. . Fall 2014 HORT6033. Molecular Plant Breeding. Lecture 9 . (09/22/2014). Genetic map construction. Mendel’s traits showed two distinct forms . Most genes do not exhibit simple inheritance. Genotypic ratios persist but phenotypic ratios may vary due to “outside-the-gene” influences including . R. r. Source: plant-genetics.kais.kyoto-u.ac.jp. ATGGGCACTGCCACT. A chromosome is a single DNA molecule complexed with histone proteins. DNA is highly compacted: DNA + histone proteins = . chromatin. PBG 430. Linkage. Linkage is the non-random . association. of two or more phenotypes or sequences in a population (genes/sequences are (almost) always inherited together). Biological explanation for linkage: genes or sequences are closely located in the same chromosome. SUTTON’S VIEW ON LINKAGE:. Sutton predicted that the chromosomes are the bearers of the units of heredity or genes and since the number of hereditary units is much larger than the number of chromosomes, therefore each chromosome must contain a number of genes.. Laura . Almasy. A meditation on what underlies linkage peaks - in which the scientist questions some of her long held, basic assumptions - as told via the parable of the Beta EEG.. Why do we get ‘loaded’ families . As there are more genes than chromosomes, it can be expected that each chromosome contains more than one gene.. The genes for different characters may be either situated on the same chromosome or on different chromosome.. UNIT


 \t\n\f\f\r\f\t\t\n\f\f\r\f\t 1.38 pairs of homosexual brothers that demonstrated possible maternal inheritance.Pedigree and linkage analysis to locate possible loci on the X chromosome responsible for inheritance ofhomosexuality. Discovery. Genetic linkage was first discovered by the British. . geneticists William Bateson, Edith Rebecca Saunders and Reginald Punnett. . shortly after Mendel's laws were rediscovered. The understanding of genetic linkage was expanded by the work of Thomas Hunt Morgan. . syntenic. genes. The genes located on the same chromosome are called . syntenic. genes.. When the . syntenic. genes are as close physical association on chromosome to one another preventing independent assortment or c.o. and are being inherited together are known as linked genes.. Sex determination. Sex in mammals is determined by two chromosomes, known as the . sex chromosomes. or . heterosomes. .. Females (XX) are the homogametic sex.. Males (XY) are the heterogametic sex..