A sell-off in the mining sector pulled the FTSE 100 over one per cent lower on Monday morning as disappointing growth figures from China and downgraded gold-price targets weighed on markets.China's first-quarter gross domestic product (GDP) growth dropped from 7.9% in the prior quarter to 7.7%, while the consensus forecast had been expecting an uptick to 8.0%. The reading still remains above China's 2013 GDP growth target of 7.5%, but will scale back hopes for any material upside surprise to official forecasts.JPMorgan has already moved to cut its forecasts after the figures this morning, reducing its 2013 GDP growth estimate from 8.2% to 7.8%. Although JP Morgan believes that the world's second-largest economy will run at a moderate growth pace this year, the broker warned that it will "continue the long-term downward trend in its growth potential".Commodities prices were hammered across the board today after the data. The price of gold further weighed down by Citigroup, which joined the growing list of brokers to cut its price targets for the precious metal. The US bank slashed its gold-price target by an average 13% over the next three years.Spot gold prices were down 5.43% at $1,402.28 an ounce, having earlier traded at the lowest level in two years. Spot silver was down a whopping 10.57% at $23.5 an ounce, while copper and platinum prices also dropped.West Texas crude was down 3.1% at $88.31 a barrel, while Brent crude was down 2.2% at $100.55 a barrel.FTSE 100: Miners suffer sell-offMetals producers were under the weather in early trading after the disappointing economic data. Fresnillo and EVRAZ were the worst hit, both down over 10% by midday, while Randgold and Polymetal weren't far behind.Polymetal was being weighed down further by a downgrade from Citigroup to 'sell'. Its price target was cut from 274p to 141p.ENRC, Xstrata, Antofagasta, Glencore and Anglo American were also suffering steep losses this morning.Rio Tinto was also lower after an Australian judge rejected the miner's plan to expand a coal mine in the wine-growing region of Hunter Valley. The judge cited "the significant, adverse, biological diversity, noise and dust, and social impacts of the project."Utilities stocks were benefitting from a reduction in risk appetite this morning as defensive sectors perform well. British gas owner Centrica was on the rise after buying several natural gas and crude oil assets in Canada. Sector peer United Utilities was also higher on M&A speculation after The Sunday Times reported that the firm has hired Goldman Sachs to help keep itself defended against any possible hostile take-over attempts. However, the company has said this was standard procedure.Oil firm Tullow was lower despite reporting a successful first flow at its Ngamia-1 well in Kenya and hydrocarbon indications at the Sabisa-1 well in Ethiopia.FTSE 250: Betfair jumps on takeover speculationOnline betting group Betfair surged early on after CVC Capital Partners confirmed that it was in talks about making an offer for the company.Mining stock Petropavlovsk was tracking the wider sector lower this morning with Citigroup adding to the selling pressure after cutting its rating for the shares to 'sell'. Other miners including Bumi, Ferrexpo and African Barrick Gold were also falling sharply.High Street bookie Ladbrokes sunk after saying that operating profits will be at the bottom of the existing market range in 2013 due to softer-than-expected trading in the first quarter.Oil and gas firm Cairn Energy was lower despite securing a long-term contract with Transocena for the Cajun Express drilling unit.Fidessa, which develops trading systems, also fell after saying that the attraction and pricing pressure seen last year has continued into the first quarter.FTSE 100 - RisersUnited Utilities Group (UU.) 742.00p +2.91%Severn Trent (SVT) 1,733.00p +1.58%easyJet (EZJ) 1,116.00p +1.18%National Grid (NG.) 801.00p +1.07%Smith & Nephew (SN.) 759.50p +0.80%Centrica (CNA) 381.70p +0.61%Aggreko (AGK) 1,800.00p +0.45%Reckitt Benckiser Group (RB.) 4,640.00p +0.43%RSA Insurance Group (RSA) 110.10p +0.18%SSE (SSE) 1,536.00p +0.13%FTSE 100 - FallersFresnillo (FRES) 1,099.00p -13.67%Evraz (EVR) 163.30p -10.96%Randgold Resources Ltd. (RRS) 4,476.00p -9.72%Polymetal International (POLY) 776.00p -9.66%Eurasian Natural Resources Corp. (ENRC) 233.70p -6.30%Antofagasta (ANTO) 953.50p -5.87%Xstrata (XTA) 984.70p -5.59%Glencore International (GLEN) 326.75p -5.07%Petrofac Ltd. (PFC) 1,333.00p -4.79%Anglo American (AAL) 1,565.50p -4.66%FTSE 250 - RisersBetfair Group (BET) 770.50p +10.15%Dixons Retail (DXNS) 35.39p +2.34%Persimmon (PSN) 1,138.00p +1.34%AZ Electronic Materials SA (DI) (AZEM) 288.30p +1.26%BH Macro Ltd. EUR Shares (BHME) € 20.54 +1.13%Man Group (EMG) 105.40p +0.96%United Drug (UDG) 293.20p +0.51%BH Global Ltd. GBP Shares (BHGG) 1,205.00p +0.42%COLT Group SA (COLT) 125.20p +0.40%Cranswick (CWK) 1,054.00p +0.38%FTSE 250 - FallersPetropavlovsk (POG) 150.90p -19.13%Bumi (BUMI) 245.60p -16.46%Ferrexpo (FXPO) 162.30p -10.73%African Barrick Gold (ABG) 170.80p -10.01%Lonmin (LMI) 254.70p -8.51%New World Resources A Shares (NWR) 196.40p -8.14%Centamin (DI) (CEY) 39.73p -7.60%Kazakhmys (KAZ) 346.40p -7.53%Ladbrokes (LAD) 191.90p -7.25%Hochschild Mining (HOC) 244.90p -6.85%BC