Heredity and Patterns of Inheritance (PDF)

PROJECT: P – TER (PRODUCTIVITY – TARGETED EXTENSIVE REVIEWERS | GRADE 12 | REVIEWER HANDOUT SENIOR HIGHSCHOOL | AUF-IS AUF HONOR CODE On my honor as an Angelenean, who lives by the core values of Mabuti, Magaling at May Malasakit sa Kapwa, I he...

PROJECT: P – TER (PRODUCTIVITY – TARGETED EXTENSIVE REVIEWERS | GRADE 12 | REVIEWER HANDOUT SENIOR HIGHSCHOOL | AUF-IS AUF HONOR CODE On my honor as an Angelenean, who lives by the core values of Mabuti, Magaling at May Malasakit sa Kapwa, I hereby pledge honesty and integrity in all my academic tasks without receiving or giving unauthorized assistance, thereby observing scholarly and intellectual standards, rules on proper citation of sources, and appropriate collection and use of data. So help me God. REMINDER This lecture is written for the purpose of guiding Angeleneans as they prepare for any upcoming activity, quiz, or examination. We still highly advise everyone to look up and review as well the sources provided by the school and the teachers to prepare better on any said assessments. Here’s to evolving through every challenge—best of luck! COLLATED BY: (DIZON, C.A., SANTOS, G.C.) // PREPARED BY: (MS. NUGUID, MS. MALLARI) TEMPLATE BY: SHS Council and BOGNOT, P.N. 0 PROJECT: P – TER (PRODUCTIVITY – TARGETED EXTENSIVE REVIEW) | GRADE 11 | LECTURE HANDOUT SENIOR HIGHSCHOOL | AUF-IS | Made by : Dizon, C.A. & Santos, G.C. | Notes from Dizon, C.A., Pamintuan, P.E. & Santos, G.C. | Handout GENERAL BIOLOGY 2 LESSON 1: HEREDITY AND PATTERNS OF INHERITANCE Fig. 1 OUTLINE I.​ Introduction II.​ Foundations of Heredity III.​ Mendel’s Laws of Inheritance IV.​ Non-Mendelian Inheritance V.​ Nature Vs. Nurture VI.​ Inheritance Patterns in Humans VII.​ Reading a Pedigree / Pedigree Analysis VIII.​ How to Read a Pedigree? Fig. 2 IX.​ X-Linked Inheritance X.​ Chromosomal Abnormalities or Changes I. INTRODUCTION A. STINK-FREE GENE ​ mutated ABCC11 Gene ○​ ABCC11 Gene - secretion of odorants and their precursors from apocrine sweat glands (armpits) B. TRAITS ​ provokes a dry and white earwax phenotype with no ​ distinguishable characteristics or features that may be axillary odor. inherited, such as hair color, eye color, blood type, or ​ the common mutation is a neutral mutation, meaning it susceptibility to certain diseases doesn’t cause any harmful effects ○​ (e.g., diabetes, depression, obesity, cancer, ​ predominant among East Asians (80%-95%) etc.) B. HEREDITY C. GENES ​ the process of inheritance ​ coined by Mendel as “factors,” ​ traits being passed from a generation (parents) to ​ units in organisms that control the expression of another (offspring) traits, which are determined by alleles C. GENETICS D. ALLELE ​ a branch of science that studies heredity (study of ​ one or more alternative forms of a gene heredity) ​ how traits are passed from one generation to the next, DOMINANT focusing on the mechanisms of inheritance, variation, and ​ the allele that masks the recessive allele; always the role of genes in determining characteristics expressed ○​ B (written using capital letters) II. FOUNDATIONS OF HEREDITY RECESSIVE A. GREGOR MENDEL (1822-1884) ​ the allele that is masked by the dominant allele; only ​ known as the “Father of Genetics” expressed in the absence of the dominant allele ​ conducted breeding experiments with the garden pea ○​ b (written using small letters) ​ formulated three laws of inheritance HOMOZYGOUS ​ homo - means “the same” GARDEN PEA (PISUM SATIVUM) ​ sometimes referred to as true-breeding ​ Mendel used this plant because: ​ describes an individual with the same allele of a gene on ​ it is easy to cultivate both homologous chromosomes ​ it has a short generation time ○​ BB or bb (same) ​ can be cross-pollinated by hand ○​ Mendel used a brush for the pollination of the garden plant/pea ​ it exhibits clear and distinguishable traits COLLATED BY: (DIZON, C.A., SANTOS, G.C.) // PREPARED BY: (MS. NUGUID, MS. MALLARI) TEMPLATE BY: SHS Council and BOGNOT, P.N. 1 PROJECT: P – TER (PRODUCTIVITY – TARGETED EXTENSIVE REVIEW) | GRADE 11 | LECTURE HANDOUT SENIOR HIGHSCHOOL | AUF-IS | Made by : Dizon, C.A. & Santos, G.C. | Notes from Dizon, C.A., Pamintuan, P.E. & Santos, G.C. | Handout HETEROZYGOUS ​ For example, in setup A, a purple flower is used as the ​ hetero - means “different” male parent, and a white flower is used as the female ​ sometimes referred to as hybrid parent. In setup B, the purple flower is used as the female ​ describes an individual with different alleles of a gene parent, and the white flower is used as the male parent. ○​ Bb (one dominant; one recessive) This allows researchers to observe whether the inheritance pattern is influenced by the sex of the parents. E. GENOTYPE ​ the set of alleles present in an individual’s chromosomes ○​ Setup A: Purple flower (male) × White flower ​ represents the organism’s genetic makeup (female). ○​ (e.g., B - black hair (dominant), b - white hair (recessive) ○​ Setup B: Purple flower (female) × White ○​ ;BB, Bb, or bb). flower (male). F. PHENOTYPE ​ Purpose: To determine if inheritance is influenced by ​ the set of observable physical traits expressed by an the sex of the parent. organism, determined by its genotype ○​ (e.g., black hair, curly hair, black eyes) P (PARENTAL GENERATION) Fig. 3 ​ the initial true-breeding plants crossed in Mendel’s experiments. ○​ BB or bb (homozygous parents) F1 (FIRST GENERATION OFFSPRING) ​ first filial generation ​ the offspring of the parental generation, often showing the dominant trait in Mendelian experiments. ○​ Bb (heterozygous offsprings) 4:0 F2 (SECOND GENERATION OFFSPRING) ​ second filial generation ​ the offspring of the F1 generation, ○​ showing a 3:1 phenotypic ratio for a G. BREEDING single-gene Mendelian trait. (3 purples, 1 ​ the process of mating or cross-pollinating organisms white) to produce offspring ○​ 1:2:1 genotypic ratio (1 BB, 2 Bb, 1 bb) ​ used to study inheritance patterns by controlling which organisms mate to observe the transmission of specific J. TEST CROSS traits ​ an experimental cross of an organism with a dominant phenotype but with an unknown genotype and TRUE-BREEDING ​ an organism with a homozygous recessive genotype ​ parents with certain traits consistently pass those traits and phenotype to every offspring (homozygous) ​ also known as a back cross ​ all offspring have the same traits as the parents, generation after generation MONOHYBRID CROSS ○​ for example, all offspring of pea plants that ​ a cross between individuals that differ in only one trait are true-bred for white flowers will also have white flowers Fig. 5 H. PUNNETT SQUARE ​ square diagram used in genetics to predict the possible genetic outcomes of a cross breeding experiment ​ helps to determine the probability of inheriting particular traits based on the genotype of the parents Fig. 4 EXAMPLE 1 ​ A = Normal, a = albinism ​ Parents = Aa ​ Find the genotype, phenotype, and their ratio I. RECIPROCAL CROSSES ​ a pair of breeding experiments performed to test the role of parental sex in inheritance. In this process, the sexes of the individuals in the parental generation are reversed in two separate setups. COLLATED BY: (DIZON, C.A., SANTOS, G.C.) // PREPARED BY: (MS. NUGUID, MS. MALLARI) TEMPLATE BY: SHS Council and BOGNOT, P.N. 2 PROJECT: P – TER (PRODUCTIVITY – TARGETED EXTENSIVE REVIEW) | GRADE 11 | LECTURE HANDOUT SENIOR HIGHSCHOOL | AUF-IS | Made by : Dizon, C.A. & Santos, G.C. | Notes from Dizon, C.A., Pamintuan, P.E. & Santos, G.C. | Handout C. LAW OF INDEPENDENT ASSORTMENT ​ an allele received for one gene does not influence the allele received for another gene. ○​ for example, the hair color of the parents affect the offspring’s hair color, but not eye or skin color DIHYBRID CROSS ​ a cross between heterozygous alleles of 2 genes Fig. 6 Fig. 8​ ​ Genotype: ○​ ¼ heterozygous normal, 2/4 or ½ heterozygous normal, ¼ homozygous affected ​ Phenotype: ○​ ¼ normal, 2/4 or ½ carrier, ¼ albino ○​ ¾ normal, ¼ albino ​ Ratio (both genotype and phenotype): ○​ 1:2:1 ○​ 3:1 (phenotype) IV. NON-MENDELIAN INHERITANCE ​ the pattern of inheritance that does not follow Mendel’s EXAMPLE 2 laws ​ W= Wire-haired, w = smooth-haired ​ Parents = WW (male); ww (female) A. INCOMPLETE DOMINANCE ​ Find the genotype, phenotype, and their ratios. ​ one allele is not fully dominant over the other ​ heterozygous phenotype is intermediate blend of 2 Fig. 7 homozygous phenotypes ○​ for example, if a homozygous white snapdragon plant is crossed with a homozygous red plant, they will have a pink offspring. B. CODOMINANCE ​ 2 alleles are simultaneously expressed ​ neither allele is dominant nor recessive ○​ for example, in some chicken, the alleles for black feathers are codominant with alleles ​ Genotype: for white feathers. If a black chicken is ○​ 4/4 heterozygous crossed with a white chicken, their offspring will have both black and white feathers. ​ Phenotype: ○​ animals: roans and speckled chickens ○​ 4/4 wire-haired Codominance — multiple alleles ​ Ratio (both genotype and phenotype): ​ some populations have 3 or more types of alleles of a ○​ 4:0 given gene (example: blood type AB) ○​ A - AA/AO = TYPE A ○​ B - BB/BO = TYPE B ○​ AB = TYPE AB III. MENDEL’S LAWS OF INHERITANCE ○​ OO = TYPE O ​ proposed by Gregor Mendel after his experiments on pea plants for seven years C. PLEIOTROPY ​ a single gene affects multiple traits A. LAW OF DOMINANCE ​ one gene, many features ​ in a heterozygous condition, dominant alleles/characters are ALWAYS expressed Examples: a.​ Marfan Syndrome (defective connective tissue): B. LAW OF SEGREGATION a mutation in the gene for fibrillin leads to various ​ when 2 traits come together in one hybrid pair, they do physical symptoms: very tall height, thin fingers, not mix. heart problems (“leaky heart”), and dislocation of lens ​ in the production of gametes, 2 copies of each factor i.​ the gene, fibrillin — makes up the elastic segregate so that offspring acquire one factor from each tissue of the heart, skin, blood, vessels, parent. tendons, etc. COLLATED BY: (DIZON, C.A., SANTOS, G.C.) // PREPARED BY: (MS. NUGUID, MS. MALLARI) TEMPLATE BY: SHS Council and BOGNOT, P.N. 3 PROJECT: P – TER (PRODUCTIVITY – TARGETED EXTENSIVE REVIEW) | GRADE 11 | LECTURE HANDOUT SENIOR HIGHSCHOOL | AUF-IS | Made by : Dizon, C.A. & Santos, G.C. | Notes from Dizon, C.A., Pamintuan, P.E. & Santos, G.C. | Handout b.​ Sickle Cell Anemia ○​ 1st - 22nd Pair: autosomes (body gene mutation that results in sickle-shaped red blood chromosomes) cells and leads to other affected traits ○​ 23rd pair: sex chromosomes ​ XX - Female D. POLYGENIC INHERITANCE ​ XY - Male ​ “qualitative inheritance” or “multifactorial inheritance” VII. READING A PEDIGREE/PEDIGREE ANALYSIS ​ multiple genes control the phenotype of an organism ​ Pedigree — allows geneticists to estimate the probability (opposite of pleiotropy) that a phenotype will reappear in future generations; it ​ alleles of 2 or more genes collectively affect a single also reveals whether a trait is associated with a dominant trait or recessive allele and whether it is on an autosome or ​ many genes, one feature sex chromosome ○​ phenotypes of traits can be height, skin color ○​ used to analyze the pattern of inheritance of (169 genes will dictate skin color), eye a particular trait throughout a family color, etc. Fig. 9​ ​ results in a bell curve (most in the middle [heterozygous], Pedigree Symbols and very few in the extremes [homozygous]) E. LETHAL ALLELES ​ phenotypic manifestation of some genes is the death of the individual organisms prior to sexual maturity ​ presence of 2 homozygous alleles is fatal ​ if heterozygous, it’s either 1 of 2 cases: ○​ heterozygous and normal ○​ heterozygous and exhibits a distinctive feature/phenotype ​ ex.: achondroplasia - dwarfism DOMINANT LETHAL ALLELES ​ AA = Death ​ Aa = Symptoms ​ aa = Normal RECESSIVE LETHAL ALLELES (consanguineous marriage is marriage between relatives) ​ AA = Normal ​ Aa = Carrier, No symptoms VIII. HOW TO READ A PEDIGREE? ​ aa = Death 1)​ Determine whether the trait is DOMINANT or F.. EPISTASIS RECESSIVE. ​ 2 or more genes contribute to a phenotype; the phenotype of 1 gene is altered by the presence of DOMINANT another. ​ one of the parents should be affected ​ covers existing gene ​ trait should not skip a generation ○​ Example: the MC1R gene causes red hair, but if there is interference from an extension RECESSIVE gene, it alters the supposed phenotype from red hair to blond hair. ​ neither parent is required to have the trait since they can be HETEROZYGOUS V. NATURE VS NURTURE ​ The environment affects the expression of a gene, which 2)​ Determine whether it is X-linked or affects the phenotype (including behavioral traits) autosomal. ​ Nature — genotype; Nurture — environment. ​ genotype + environment = phenotype X-LINKED ○​ ex.: water fleas being red in color in a ​ patterns in sex polluted environment ○​ DOMINANT: TRAITS: affected fathers pass the trait to all their daughters; no carriers VI. INHERITANCE PATTERNS IN HUMANS ○​ RECESSIVE TRAITS: males are more ​ inheritance patterns in humans include the following: commonly affected (mothers pass down to ○​ Autosomal Dominant their sons) ○​ Autosomal Recessive AUTOSOMAL ○​ X-Linked Dominant ​ both male and females are equally likely to be affected ○​ X-Linked Recessive (usually in equal proportions) A. TAKE NOTE ​ Humans have 46 chromosomes, inherited as 23 from the father and 23 from the mother, organized into 23 pairs. B. TRAITS COLLATED BY: (DIZON, C.A., SANTOS, G.C.) // PREPARED BY: (MS. NUGUID, MS. MALLARI) TEMPLATE BY: SHS Council and BOGNOT, P.N. 4 PROJECT: P – TER (PRODUCTIVITY – TARGETED EXTENSIVE REVIEW) | GRADE 11 | LECTURE HANDOUT SENIOR HIGHSCHOOL | AUF-IS | Made by : Dizon, C.A. & Santos, G.C. | Notes from Dizon, C.A., Pamintuan, P.E. & Santos, G.C. | Handout A. AUTOSOMAL DOMINANT ALBINISM ​ location of gene: autosomes or non-sex chromosomes ​ abnormally low levels of melanin ​ a single copy of the mutated gene (from one parent) is ​ skin, hair, or eye pigmentation may be reduced or missing enough to cause the disorder. ​ affected sex: both male and female TAY-SACHS DISEASE Fig. 10 ​ absence of an enzyme that helps break down fatty substances ​ fatty substance build up to toxic levels in the brain and spinal cord and affect the function of the nerve cells ​ mutation in chromosome 15 IX. X-LINKED INHERITANCE ​ genes located on the X chromosome can be inherited in either a dominant or recessive manner ​ since MALES only have one X chromosome (XY), any mutated gene on the X chromosome—dominant or recessive—will result in disease ​ Fathers can pass x-linked traits ONLY to their daughters (as sons only get the Y chromosome from their fathers). ​ In contrast, mothers pass x-linked genes to their sons Fig. 12 ACHONDROPLASIA ​ example of lethal alleles (non-mendelian inheritance) ​ a form of hereditary dwarfism ​ mutation in gene for growth factor ​ affected have unusually short stature, with arms and legs relative to the torso size HUTCHINSON-GILFORD PROGERIA ​ symptoms: dramatic, rapid appearance of aging beginning in childhood ​ usually die of heart attack at young age due to hardening A. X-LINKED DOMINANT of arteries or atherosclerosis ​ a mutation in 1 copy of an x-linked gene will result in disease for both males and females. HUNTINGTON’S DISEASE ​ if the mother is affected, both males and females are ​ an inherited disorder that causes nerve cells (neurons) to affected in the generation. gradually break down and die ​ if the father is affected, females are more frequently ​ the disease attacks areas of the brain that help to control affected; no sons will be affected. voluntary movement, as well as other areas Fig. 13 B. AUTOSOMAL RECESSIVE ​ two copies of the mutated gene (from both parents) will cause the disorder ​ affected sex: both male and female ○​ heterozygous individuals are called “carriers” because they have the allele but not the trait Fig. 11 COLLATED BY: (DIZON, C.A., SANTOS, G.C.) // PREPARED BY: (MS. NUGUID, MS. MALLARI) TEMPLATE BY: SHS Council and BOGNOT, P.N. 5 PROJECT: P – TER (PRODUCTIVITY – TARGETED EXTENSIVE REVIEW) | GRADE 11 | LECTURE HANDOUT SENIOR HIGHSCHOOL | AUF-IS | Made by : Dizon, C.A. & Santos, G.C. | Notes from Dizon, C.A., Pamintuan, P.E. & Santos, G.C. | Handout RETT SYNDROME X. CHROMOSOMAL ABNORMALITIES OR CHANGES ​ becomes apparent after 6-18 months in females A. POLYPLOIDY ​ symptoms: disability in language and coordination ​ species with three or more sets of chromosomes ​ affected people usually show slower growth, difficulty in ​ common in plants, insects, and other animals, but not walking, and smaller brain size than normal human ​ affected males usually die shortly after birth ○​ most cases arise due to new mutations on B. ANEUPLOIDY the X chromosome. ​ too many or too few copies of a particular chromosome ​ usually outcome of nondisjunction, feature of FRAGILE X SYNDROME chromosomes to separate during meiosis ​ symptom: developmental problems — learning disabilities and cognitive impairment PATAU SYNDROME (TRISOMY 13) ​ anxiety and hyperactive behavior such as fidgeting or ​ caused by the presence of an extra copy of chromosome impulsive actions 13 ​ usually, males are more severely affected by this ​ disrupts normal development, leading to severe disorder than females intellectual disabilities, physical abnormalities, and often life-threatening health issues B. X-LINKED RECESSIVE ​ characterized by severe physical and intellectual ​ most often occur in males (one X chromosome) abnormalities, including ​ a single recessive gene on that X chromosome will cause ○​ cleft lip or palate, extra fingers or toes the disease in males (polydactyly), heart defects, severe brain ​ females (XX) must inherit the recessive allele on both abnormalities, low birth weight, and small or X chromosome to have the disease poorly developed eyes (microphthalmia) ​ families with an x-linked recessive disorder often have ​ due to the severity of these complications, most infants do affected males, but rarely affected females, in each not survive beyond their first year generation DOWN SYNDROME (TRISOMY 21) Fig. 14 ​ due to an extra copy of chromosome 21 ​ affected have some degree of mental retardation, some impairment of physical growth, and a specific facial appearance KLINEFELTER SYNDROME ​ males have an extra X chromosome (47, XXY) ​ this inhibits growth of genitalia, hormone production, and fertility TURNER SYNDROME ​ females have a missing X chromosome (45, XO) ​ causes symptoms like short height, failure of ovary development, and heart defects The following information on this handout is referred from the recommended references and textbooks. Please review them as well. Thank you, and good luck! Let your traits shine! DUCHENNE MUSCULAR DYSTROPHY (DMD) ​ mutation in the dystrophia gene lead to progressive muscle fiber degeneration and weakness ​ primarily affect males, symptoms begin around the age of 4 and progress very quickly RED-GREEN COLOR BLINDNESS ​ most common color deficiency ​ an individual can’t see shades red and green the same way as people with normal color perception do HEMOPHILIA ​ blood does not clot properly ​ mutations in the clotting factors genes COLLATED BY: (DIZON, C.A., SANTOS, G.C.) // PREPARED BY: (MS. NUGUID, MS. MALLARI) TEMPLATE BY: SHS Council and BOGNOT, P.N. 6